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I'm doing project with beacon.
smartphone(android client) collect rssi nearby beacons and send to python(server)
< current application's function >
-> when new beacon signal captured, display beacon's rssi value, Mac address
-> connect with tcp and send to python server in real time (Problem!!)
when using method(send text message to python server) with buttonclickevent,
connecting and sending text message works well.
but when i use method with listview adapter(using ArrayMap),
connecting works well, but can't send rssi.
more detail, infinite loop for waiting data
I think there is a problem between using runOnUiThread and data sending but i'm not sure about it.
Mainactivity
package midascon.example.scanlist;
import com.hanvitsi.midascon.Beacon;
import com.hanvitsi.midascon.BeaconCallback;
import com.hanvitsi.midascon.MidasApplication;
import com.hanvitsi.midascon.manager.ContextManager;
import android.Manifest;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.os.Bundle;
import android.os.StrictMode;
import android.support.v4.app.ActivityCompat;
import android.support.v4.content.ContextCompat;
import android.util.Log;
import android.widget.ListView;
public class MainActivity extends Activity implements BeaconCallback, Runnable
{
private static final int MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION = 100;
private ContextManager contextManager;
private BeaconListAdapter adapter;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
if (android.os.Build.VERSION.SDK_INT > 9) { StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build(); StrictMode.setThreadPolicy(policy); }
checkPermission();
contextManager = getMidasApplication().getContextManager();
contextManager.getBeaconSettings().setMidasScanMode(false);
adapter = new BeaconListAdapter(getBaseContext()); // Beacon list adapter
ListView listView = (ListView) findViewById(R.id.listView);
listView.setAdapter(adapter);
}
#Override
public void onBeaconCallback(int status, Beacon beacon) // add beacon to list when beacon signal captured
{
switch (status) {
case STATUS_CODE_ENTER:
case STATUS_CODE_UPDATE:
if (adapter != null)
adapter.addBeacon(beacon);
break;
case STATUS_CODE_EXIT:
if (adapter != null)
adapter.removeBeacon(beacon);
break;
default:
break;
}
runOnUiThread(this);
}
public void checkPermission() // allow permission
{
if(checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED){
ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
}
}
#Override
public void run() {
if (adapter != null)
adapter.notifyDataSetChanged();
}
// call name class setting by AndroidManifest.xml
public MidasApplication getMidasApplication() {
return (MidasApplication) getApplication();
}
#Override
protected void onResume() {
super.onResume();
if (ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.ACCESS_FINE_LOCATION)) {
ActivityCompat.requestPermissions(this, new String[] { Manifest.permission.ACCESS_FINE_LOCATION }, MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);
}
else
{
ActivityCompat.requestPermissions(this, new String[] { Manifest.permission.ACCESS_FINE_LOCATION }, MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);
}
}
else {
if (BluetoothAdapter.getDefaultAdapter().isEnabled()) {
// register callback
contextManager.setBeaconCallback(this);
contextManager.startLeScan();
} else {
contextManager.stopLeScan();
Intent settingsIntent = new Intent(android.provider.Settings.ACTION_BLUETOOTH_SETTINGS);
startActivity(settingsIntent);
}
}
}
#Override
protected void onPause() {
super.onPause();
contextManager.stopLeScan();
}
}
midas is company that made beacon
BeaconListAdapter
public class BeaconListAdapter extends BaseAdapter
{
private final LayoutInflater inflater;
private int count; //counting beacon
private final ArrayMap<String, Beacon> itemMap = new ArrayMap<String, Beacon>();
private final int padding;
public int CurBeaconHave = 2;
private Handler mHandler;
public int port = 9999;
public int initcnt = 0;
public int stackcnt = 0;
public int serveractivate = 0;
public int praccnt = 0;
public static String Sendrssi = "";
public Socket socket = null;
public BeaconListAdapter(Context context) {
super();
padding = (int) context.getResources().getDimension(R.dimen.activity_vertical_margin);
this.inflater = LayoutInflater.from(context);
}
public int addBeacon(Beacon beacon) {
synchronized (itemMap) {
itemMap.put(beacon.getMac(), beacon);
count = itemMap.size();
return count;
}
}
public int removeBeacon(Beacon beacon) {
synchronized (itemMap) {
itemMap.remove(beacon.getMac());
count = itemMap.size();
return count;
}
}
#Override
public int getCount() {
return count;
}
#Override
public Beacon getItem(int position) {
synchronized (itemMap) {
return itemMap.valueAt(position);
}
}
void ToPython() {
try {
String tmp = Sendrssi;
PrintWriter out = new PrintWriter(new BufferedWriter(new OutputStreamWriter(socket.getOutputStream())));
out.println(tmp);
out.flush();
Log.d("sendrssi ",tmp);
}
catch (Exception e) {
e.printStackTrace();
}
}
/*public void ToPython() {
try {
String tmp = Sendrssi;
BufferedWriter out = new BufferedWriter(new OutputStreamWriter(socket.getOutputStream()));
out.write(tmp);
out.newLine();
out.flush();
Log.d("Sending. Rssi : ", tmp);
} catch (Exception e) {
e.printStackTrace();
}
}*/
void connect() {
Log.w("state", "connecting..");
Thread checkUpdate = new Thread() {
public void run() {
String newip = "192.168.0.4";
try {
socket = new Socket(newip, port);
Log.w("state ", "server connected");
serveractivate = 1;
} catch (IOException e1) {
Log.w("state ", "failed");
e1.printStackTrace();
System.out.println("error :" + e1.getMessage());
}
}
};
checkUpdate.start();
}
#Override
public long getItemId(int position) {
return position;
}
public void stopsocket()
{
try
{
socket.close();
} catch (IOException e){
e.printStackTrace();
}
}
#Override
public View getView(int position, View convertView, ViewGroup parent) {
TextView textView = null;
if (convertView == null)
{
convertView = inflater.inflate(android.R.layout.simple_list_item_1, parent, false);
textView = (TextView) convertView.findViewById(android.R.id.text1);
textView.setBackgroundColor(Color.WHITE);
textView.setTextColor(Color.BLACK);
textView.setPadding(padding, padding, padding, padding);
convertView.setTag(textView);
}
else
{
textView = (TextView) convertView.getTag();
}
Beacon item = getItem(position);
int temprssi = item.getRssi();
while(serveractivate == 0)
{
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
Log.d("Connect State : ","wait for Server Connect...");
connect();
}
if(serveractivate == 1)
{
try {
socket.setTcpNoDelay(true);
} catch (SocketException e) {
e.printStackTrace();
}
}
int[] values = BeaconUtils.getAccelerometer(item);
textView.setText(String.format("[%s]\nMAC : %s\nRssi : %d\n", item.getType() == Beacon.TYPE_MIDAS ? "Midascon" : "Beacon", item.getMac(),temprssi));
if(count == CurBeaconHave)
{
if(stackcnt == CurBeaconHave)
{
ToPython();
stackcnt = 0;
Sendrssi = "";
}
else if(stackcnt != CurBeaconHave)
{
Sendrssi = Sendrssi + temprssi + " " ;//+ (temprssi - 3) + " " + (temprssi + 5) + " " + (temprssi - 7) + " ";
stackcnt++;
}
}
return convertView;
}
}
total code line is about 400 line, so i upload code that have problem i think.
thank you for reading and try to solve my problem
if you need another code i'll upload it
Note that i'm not good at english, so you may have difficult with reading and understand. sorry for that :(
problem solved.
It's not a normal method, so please be patient.
BeaconListadapter in connect method, i use thread.
but i don't use thread in Topython method.
because of this, there's problem with socket information when send data
so i delete thread in connect method and run and method
in main thread(i know this is idiot thing)
if you use like me, probably use connect and send data method in one thread
I have an HttpClient that I am using for a REST API. However I am having trouble setting up the Authorization header. I need to set the header to the token I received from doing my OAuth request.
I saw some code for .NET that suggests the following,
httpClient.DefaultRequestHeaders.Authorization = new Credential(OAuth.token);
However the Credential class does that not exist in WinRT. Anyone have any ideas how to set the Authorization header?
So the way to do it is the following,
httpClient.DefaultRequestHeaders.Authorization =
new AuthenticationHeaderValue("Bearer", "Your Oauth token");
request.DefaultRequestHeaders.Authorization =
new AuthenticationHeaderValue(
"Basic", Convert.ToBase64String(
System.Text.ASCIIEncoding.ASCII.GetBytes(
$"{yourusername}:{yourpwd}")));
I look for a good way to deal with this issue and I am looking at the same question. Hopefully, this answer will be helping everyone who has the same problem likes me.
using (var client = new HttpClient())
{
var url = "https://www.theidentityhub.com/{tenant}/api/identity/v1";
client.DefaultRequestHeaders.Add("Authorization", "Bearer " + accessToken);
var response = await client.GetStringAsync(url);
// Parse JSON response.
....
}
reference from https://www.theidentityhub.com/hub/Documentation/CallTheIdentityHubApi
As it is a good practice to reuse the HttpClient instance, for performance and port exhaustion problems, and because none of the answers give this solution (and even leading you toward bad practices :( ), I put here a link towards the answer I made on a similar question :
https://stackoverflow.com/a/40707446/717372
Some sources on how to use HttpClient the right way:
https://aspnetmonsters.com/2016/08/2016-08-27-httpclientwrong/
https://blogs.msdn.microsoft.com/alazarev/2017/12/29/disposable-finalizers-and-httpclient/
I suggest to you:
HttpClient.DefaultRequestHeaders.Add("Authorization", "Bearer <token>");
And then you can use it like that:
var response = await client.GetAsync(url);
if (response.IsSuccessStatusCode)
{
responseMessage = await response.Content.ReadAsAsync<ResponseMessage>();
}
In the case you want to send HttpClient request with Bearer Token, this code can be a good solution:
var requestMessage = new HttpRequestMessage
{
Method = HttpMethod.Post,
Content = new StringContent(".....", Encoding.UTF8, "application/json"),
RequestUri = new Uri(".....")
};
requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Bearer", "Your token");
var response = await _httpClient.SendAsync(requestMessage);
I was setting the bearer token
httpClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", token);
It was working in one endpoint, but not another. The issue was that I had lower case b on "bearer". After change now it works for both api's I'm hitting. Such an easy thing to miss if you aren't even considering it as one of the haystacks to look in for the needle.
Make sure to have "Bearer" - with capital.
Use Basic Authorization And Json Parameters.
using (HttpClient client = new HttpClient())
{
var request_json = "your json string";
var content = new StringContent(request_json, Encoding.UTF8, "application/json");
var authenticationBytes = Encoding.ASCII.GetBytes("YourUsername:YourPassword");
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",
Convert.ToBase64String(authenticationBytes));
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
var result = await client.PostAsync("YourURL", content);
var result_string = await result.Content.ReadAsStringAsync();
}
For anyone finding this old thread now (2021), please look at this documentation about HttpClientFactory which is injectable and will also re-run on each request avoiding expired tokens which will make it useful for bearer tokens, generated clients, pooling etc.
TL;DR: Use HttpClientFactory and a DelegatingHandler which will act as middleware on all outgoing requests with your configured client.
This is how I add my bearer for Azure Identity (managed by Azure) but you can get the token however you want of course;
using Microsoft.Azure.Services.AppAuthentication;
using System.Net.Http;
using System.Threading;
using System.Threading.Tasks;
public class BearerTokenHandler : DelegatingHandler
{
public BearerTokenHandler(AzureServiceTokenProvider tokenProvider, string resource)
{
TokenProvider = tokenProvider;
Resource = resource;
}
public AzureServiceTokenProvider TokenProvider { get; }
public string Resource { get; }
protected override async Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
if (!request.Headers.Contains("Authorization"))
{
// Fetch your token here
string token = await TokenProvider.GetAccessTokenAsync(Resource);
request.Headers.Authorization = new System.Net.Http.Headers.AuthenticationHeaderValue("Bearer", token);
}
return await base.SendAsync(request, cancellationToken);
}
}
I configure my typed clients (generated with NSwag) like this in Startup;
var accessTokenProvider = new AzureServiceTokenProvider("<your-connection-string-for-access-token-provider>");
builder.Services.AddHttpClient<IOrdersClient, OrdersClient>().ConfigureHttpClient(async conf =>
{
conf.BaseAddress = new Uri("<your-api-base-url>");
}).AddHttpMessageHandler(() => new BearerTokenHandler(accessTokenProvider, "https://your-azure-tenant.onmicrosoft.com/api"));
Then you can inject your IOrdersClient wherever you like and all requests will have the bearer.
If you want to reuse the HttpClient, it is advised to not use the DefaultRequestHeaders as they are used to send with each request.
You could try this:
var requestMessage = new HttpRequestMessage
{
Method = HttpMethod.Post,
Content = new StringContent("...", Encoding.UTF8, "application/json"),
RequestUri = new Uri("...")
};
requestMessage.Headers.Authorization = new AuthenticationHeaderValue("Basic",
Convert.ToBase64String(System.Text.ASCIIEncoding.ASCII.GetBytes($"{user}:{password}")));
var response = await _httpClient.SendAsync(requestMessage);
To set basic authentication with C# HttpClient. The following code is working for me.
using (var client = new HttpClient())
{
var webUrl ="http://localhost/saleapi/api/";
var uri = "api/sales";
client.BaseAddress = new Uri(webUrl);
client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
client.DefaultRequestHeaders.ConnectionClose = true;
//Set Basic Auth
var user = "username";
var password = "password";
var base64String =Convert.ToBase64String( Encoding.ASCII.GetBytes($"{user}:{password}"));
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",base64String);
var result = await client.PostAsJsonAsync(uri, model);
return result;
}
This is how i have done it:
using (HttpClient httpClient = new HttpClient())
{
Dictionary<string, string> tokenDetails = null;
var messageDetails = new Message { Id = 4, Message1 = des };
HttpClient client = new HttpClient();
client.BaseAddress = new Uri("http://localhost:3774/");
var login = new Dictionary<string, string>
{
{"grant_type", "password"},
{"username", "sa#role.com"},
{"password", "lopzwsx#23"},
};
var response = client.PostAsync("Token", new FormUrlEncodedContent(login)).Result;
if (response.IsSuccessStatusCode)
{
tokenDetails = JsonConvert.DeserializeObject<Dictionary<string, string>>(response.Content.ReadAsStringAsync().Result);
if (tokenDetails != null && tokenDetails.Any())
{
var tokenNo = tokenDetails.FirstOrDefault().Value;
client.DefaultRequestHeaders.Add("Authorization", "Bearer " + tokenNo);
client.PostAsJsonAsync("api/menu", messageDetails)
.ContinueWith((postTask) => postTask.Result.EnsureSuccessStatusCode());
}
}
}
This you-tube video help me out a lot. Please check it out.
https://www.youtube.com/watch?v=qCwnU06NV5Q
6 Years later but adding this in case it helps someone.
https://www.codeproject.com/Tips/996401/Authenticate-WebAPIs-with-Basic-and-Windows-Authen
var authenticationBytes = Encoding.ASCII.GetBytes("<username>:<password>");
using (HttpClient confClient = new HttpClient())
{
confClient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic",
Convert.ToBase64String(authenticationBytes));
confClient.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue(Constants.MediaType));
HttpResponseMessage message = confClient.GetAsync("<service URI>").Result;
if (message.IsSuccessStatusCode)
{
var inter = message.Content.ReadAsStringAsync();
List<string> result = JsonConvert.DeserializeObject<List<string>>(inter.Result);
}
}
UTF8 Option
request.DefaultRequestHeaders.Authorization =
new AuthenticationHeaderValue(
"Basic", Convert.ToBase64String(
System.Text.Encoding.UTF8.GetBytes(
$"{yourusername}:{yourpwd}")));
Using AuthenticationHeaderValue class of System.Net.Http assembly
public AuthenticationHeaderValue(
string scheme,
string parameter
)
we can set or update existing Authorization header for our httpclient like so:
httpclient.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Bearer", TokenResponse.AccessToken);
BaseWebApi.cs
public abstract class BaseWebApi
{
//Inject HttpClient from Ninject
private readonly HttpClient _httpClient;
public BaseWebApi(HttpClient httpclient)
{
_httpClient = httpClient;
}
public async Task<TOut> PostAsync<TOut>(string method, object param, Dictionary<string, string> headers, HttpMethod httpMethod)
{
//Set url
HttpResponseMessage response;
using (var request = new HttpRequestMessage(httpMethod, url))
{
AddBody(param, request);
AddHeaders(request, headers);
response = await _httpClient.SendAsync(request, cancellationToken);
}
if(response.IsSuccessStatusCode)
{
return await response.Content.ReadAsAsync<TOut>();
}
//Exception handling
}
private void AddHeaders(HttpRequestMessage request, Dictionary<string, string> headers)
{
request.Headers.Accept.Clear();
request.Headers.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
if (headers == null) return;
foreach (var header in headers)
{
request.Headers.Add(header.Key, header.Value);
}
}
private static void AddBody(object param, HttpRequestMessage request)
{
if (param != null)
{
var content = JsonConvert.SerializeObject(param);
request.Content = new StringContent(content);
request.Content.Headers.ContentType = new MediaTypeHeaderValue("application/json");
}
}
SubWebApi.cs
public sealed class SubWebApi : BaseWebApi
{
public SubWebApi(HttpClient httpClient) : base(httpClient) {}
public async Task<StuffResponse> GetStuffAsync(int cvr)
{
var method = "get/stuff";
var request = new StuffRequest
{
query = "GiveMeStuff"
}
return await PostAsync<StuffResponse>(method, request, GetHeaders(), HttpMethod.Post);
}
private Dictionary<string, string> GetHeaders()
{
var headers = new Dictionary<string, string>();
var basicAuth = GetBasicAuth();
headers.Add("Authorization", basicAuth);
return headers;
}
private string GetBasicAuth()
{
var byteArray = Encoding.ASCII.GetBytes($"{SystemSettings.Username}:{SystemSettings.Password}");
var authString = Convert.ToBase64String(byteArray);
return $"Basic {authString}";
}
}
In net .core you can use with Identity Server 4
var client = new HttpClient();
client.SetBasicAuthentication(userName, password);
or
var client = new HttpClient();
client.SetBearerToken(token);
see https://github.com/IdentityModel/IdentityModel/blob/main/src/Client/Extensions/AuthorizationHeaderExtensions.cs
this could works, if you are receiving a json or an xml from the service and i think this can give you an idea about how the headers and the T type works too, if you use the function MakeXmlRequest(put results in xmldocumnet) and MakeJsonRequest(put the json in the class you wish that have the same structure that the json response) in the next way
/*-------------------------example of use-------------*/
MakeXmlRequest<XmlDocument>("your_uri",result=>your_xmlDocument_variable = result,error=>your_exception_Var = error);
MakeJsonRequest<classwhateveryouwant>("your_uri",result=>your_classwhateveryouwant_variable=result,error=>your_exception_Var=error)
/*-------------------------------------------------------------------------------*/
public class RestService
{
public void MakeXmlRequest<T>(string uri, Action<XmlDocument> successAction, Action<Exception> errorAction)
{
XmlDocument XMLResponse = new XmlDocument();
string wufooAPIKey = ""; /*or username as well*/
string password = "";
StringBuilder url = new StringBuilder();
url.Append(uri);
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url.ToString());
string authInfo = wufooAPIKey + ":" + password;
authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
request.Timeout = 30000;
request.KeepAlive = false;
request.Headers["Authorization"] = "Basic " + authInfo;
string documento = "";
MakeRequest(request,response=> documento = response,
(error) =>
{
if (errorAction != null)
{
errorAction(error);
}
}
);
XMLResponse.LoadXml(documento);
successAction(XMLResponse);
}
public void MakeJsonRequest<T>(string uri, Action<T> successAction, Action<Exception> errorAction)
{
string wufooAPIKey = "";
string password = "";
StringBuilder url = new StringBuilder();
url.Append(uri);
HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(url.ToString());
string authInfo = wufooAPIKey + ":" + password;
authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
request.Timeout = 30000;
request.KeepAlive = false;
request.Headers["Authorization"] = "Basic " + authInfo;
// request.Accept = "application/json";
// request.Method = "GET";
MakeRequest(
request,
(response) =>
{
if (successAction != null)
{
T toReturn;
try
{
toReturn = Deserialize<T>(response);
}
catch (Exception ex)
{
errorAction(ex);
return;
}
successAction(toReturn);
}
},
(error) =>
{
if (errorAction != null)
{
errorAction(error);
}
}
);
}
private void MakeRequest(HttpWebRequest request, Action<string> successAction, Action<Exception> errorAction)
{
try{
using (var webResponse = (HttpWebResponse)request.GetResponse())
{
using (var reader = new StreamReader(webResponse.GetResponseStream()))
{
var objText = reader.ReadToEnd();
successAction(objText);
}
}
}catch(HttpException ex){
errorAction(ex);
}
}
private T Deserialize<T>(string responseBody)
{
try
{
var toReturns = JsonConvert.DeserializeObject<T>(responseBody);
return toReturns;
}
catch (Exception ex)
{
string errores;
errores = ex.Message;
}
var toReturn = JsonConvert.DeserializeObject<T>(responseBody);
return toReturn;
}
}
}
It may be easier to use an existing library.
For example, the extension methods below are added with Identity Server 4
https://www.nuget.org/packages/IdentityModel/
public static void SetBasicAuthentication(this HttpClient client, string userName, string password);
//
// Summary:
// Sets a basic authentication header.
//
// Parameters:
// request:
// The HTTP request message.
//
// userName:
// Name of the user.
//
// password:
// The password.
public static void SetBasicAuthentication(this HttpRequestMessage request, string userName, string password);
//
// Summary:
// Sets a basic authentication header for RFC6749 client authentication.
//
// Parameters:
// client:
// The client.
//
// userName:
// Name of the user.
//
// password:
// The password.
public static void SetBasicAuthenticationOAuth(this HttpClient client, string userName, string password);
//
// Summary:
// Sets a basic authentication header for RFC6749 client authentication.
//
// Parameters:
// request:
// The HTTP request message.
//
// userName:
// Name of the user.
//
// password:
// The password.
public static void SetBasicAuthenticationOAuth(this HttpRequestMessage request, string userName, string password);
//
// Summary:
// Sets an authorization header with a bearer token.
//
// Parameters:
// client:
// The client.
//
// token:
// The token.
public static void SetBearerToken(this HttpClient client, string token);
//
// Summary:
// Sets an authorization header with a bearer token.
//
// Parameters:
// request:
// The HTTP request message.
//
// token:
// The token.
public static void SetBearerToken(this HttpRequestMessage request, string token);
//
// Summary:
// Sets an authorization header with a given scheme and value.
//
// Parameters:
// client:
// The client.
//
// scheme:
// The scheme.
//
// token:
// The token.
public static void SetToken(this HttpClient client, string scheme, string token);
//
// Summary:
// Sets an authorization header with a given scheme and value.
//
// Parameters:
// request:
// The HTTP request message.
//
// scheme:
// The scheme.
//
// token:
// The token.
public static void SetToken(this HttpRequestMessage request, string scheme, string token);
Firstly, I wouldn't use HttpClient directly. It's too easy to make mistakes - particularly in the area of headers. The DefaultHeadersCollection is not immutable and not thread-safe because other parts of the app can change the headers on you. It's best to set the headers when you make the call. If you are working with an abstraction, and that is recommended because the classes in this area are a bit of a mess, you would want to have a headers collection and put those on your HttpRequestMessage before you send it. You need to make sure you put the content headers on the content, and not the message.
Code Reference
foreach (var headerName in request.Headers.Names)
{
//"Content-Type"
if (string.Compare(headerName, HeadersExtensions.ContentTypeHeaderName, StringComparison.OrdinalIgnoreCase) == 0)
{
//Note: not sure why this is necessary...
//The HttpClient class seems to differentiate between content headers and request message headers, but this distinction doesn't exist in the real world...
//TODO: Other Content headers
httpContent?.Headers.Add(HeadersExtensions.ContentTypeHeaderName, request.Headers[headerName]);
}
else
{
httpRequestMessage.Headers.Add(headerName, request.Headers[headerName]);
}
}
Here is a data structure that you could use to send the request which includes the headers.
Code Reference
public interface IRequest
{
CancellationToken CancellationToken { get; }
string? CustomHttpRequestMethod { get; }
IHeadersCollection Headers { get; }
HttpRequestMethod HttpRequestMethod { get; }
AbsoluteUrl Uri { get; }
}
public interface IRequest<TBody> : IRequest
{
TBody? BodyData { get; }
}
And, a headers collection:
Code Reference
public sealed class HeadersCollection : IHeadersCollection
{
#region Fields
private readonly IDictionary<string, IEnumerable<string>> dictionary;
#endregion
#region Public Constructors
public HeadersCollection(IDictionary<string, IEnumerable<string>> dictionary) => this.dictionary = dictionary;
public HeadersCollection(string key, string value) : this(ImmutableDictionary.CreateRange(
new List<KeyValuePair<string, IEnumerable<string>>>
{
new(key, ImmutableList.Create(value))
}
))
{
}
#endregion Public Constructors
#region Public Properties
public static HeadersCollection Empty { get; } = new HeadersCollection(ImmutableDictionary.Create<string, IEnumerable<string>>());
public IEnumerable<string> Names => dictionary.Keys;
IEnumerable<string> IHeadersCollection.this[string name] => dictionary[name];
#endregion Public Properties
#region Public Methods
public bool Contains(string name) => dictionary.ContainsKey(name);
public IEnumerator<KeyValuePair<string, IEnumerable<string>>> GetEnumerator() => dictionary.GetEnumerator();
IEnumerator IEnumerable.GetEnumerator() => dictionary.GetEnumerator();
public override string ToString() => string.Join("\r\n", dictionary.Select(kvp => $"{kvp.Key}: {string.Join(", ", kvp.Value)}\r\n"));
#endregion
}
See all the working code and examples here.
You can too to use the follow exemple, that it use IHttpClientFactory:
readonly IHttpClientFactory _httpClientFactory;
public HTTPClientHelper(IHttpClientFactory httpClientFactory, string clientName = null)
{
this._httpClientFactory = httpClientFactory;
}
public Task<T> GetAsync(string url, string token) {
var client = _httpClientFactory.CreateClient(_clientName);
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue(JwtBearerDefaults.AuthenticationScheme, token);
using (HttpResponseMessage response = await _client.GetAsync(url)){
......
}
}
I came across this old thread. The problem I had was that I know to use a static HttpClient, but my token needs refreshing every 59 minutes.
So I could have used HttpClientFactory, but because one of my projects was still in .NET 4.8, I created a class that inherited from HttpClient so I have similar code in all projects. A secret is needed to be able to get the token (I'm using identityserver4).
I then set that as a singleton in DI (I'm using Ninject here):
Bind<MyHttpClient>().ToMethod(c =>
{
var accessKey = ConfigurationManager.AppSettings["AccessKey"];
var client = new MyHttpClient(accessKey)
{
BaseAddress = new Uri(MyUrls.MyApiBaseUrl)
};
client.DefaultRequestHeaders.Accept.Clear();
client.DefaultRequestHeaders.Accept.Add(new System.Net.Http.Headers.MediaTypeWithQualityHeaderValue("application/json"));
return client;
}).InSingletonScope();
Then the class itself - named after the API it is used to access:
public class MyHttpClient : BaseHttpClient
{
private static readonly HttpClient _authHttpClient = new HttpClient();
private string _secret;
public MyHttpClient(string secret)
{
_secret = secret;
}
/// <summary>
/// Add the token to each and every request, cached for 1 minute less than the token's lifetime
/// </summary>
/// <param name="request"></param>
/// <param name="cancellationToken"></param>
/// <returns></returns>
/// <exception cref="Exception"></exception>
public override Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, CancellationToken cancellationToken)
{
cancellationToken.ThrowIfCancellationRequested();
var cacheSeconds = 3600 - 60; // Default of 59 minutes
var token = CacheHelper<string>.Get("MyToken", cacheSeconds * 60, () =>
{
var authorityUrl = MyUrls.AuthServerUrl;
// discover endpoints from metadata
DiscoveryDocumentResponse disco;
disco = _authHttpClient.GetDiscoveryDocumentAsync(authorityUrl).Result;
if (disco.IsError)
{
throw new Exception("Error getting discovery document: " + disco.Error);
}
// request token
var tokenResponse = _authHttpClient.RequestClientCredentialsTokenAsync(new ClientCredentialsTokenRequest
{
Address = disco.TokenEndpoint,
ClientId = "myapp",
ClientSecret = _secret,
Scope = "myapi"
}).Result;
if (tokenResponse.IsError)
{
throw new Exception("Error getting token: " + tokenResponse.Error);
}
if (tokenResponse.ExpiresIn < cacheSeconds + 60)
{
throw new Exception($"Token expires in {tokenResponse.ExpiresIn}s, which is less than {cacheSeconds + 60}");
}
if (tokenResponse.ExpiresIn > cacheSeconds + 60)
{
Log.Warn().Message($"Token expiry in {tokenResponse.ExpiresIn}s, which is greater than {cacheSeconds}").Write();
}
return tokenResponse.AccessToken;
});
// THIS IS THE BIT - Assign this inside a SendAsync override and you are done!
request.Headers.Authorization = new AuthenticationHeaderValue("Bearer", token);
return base.SendAsync(request, cancellationToken);
}
}
Finally just for completeness, my CacheHelper class looks like this:
public static class CacheHelper<T>
{
private static readonly object _locker = new object();
public static T Get(string cacheName, int cacheTimeoutSeconds, Func<T> func)
{
var obj = MemoryCache.Default.Get(cacheName, null);
if (obj != null) return (T)obj;
lock (_locker)
{
obj = MemoryCache.Default.Get(cacheName, null);
if (obj == null)
{
obj = func();
var cip = new CacheItemPolicy
{
AbsoluteExpiration = new DateTimeOffset(DateTime.UtcNow.AddSeconds(cacheTimeoutSeconds))
};
MemoryCache.Default.Set(cacheName, obj, cip);
}
}
return (T)obj;
}
}
Oauth Process flow is complex and there is always a room for one error or another.
My suggestion will be to always use the boilerplate code and a set of libraries for OAuth authentication flow.It will make your life easier.
Here is the link for the set of libraries.OAuth Libraries for .Net
If you are using Visual Studio IISExpress debug mode and connecting to the HTTP port rather than the HTTPS port you may find that the auth headers are being dropped.
Switch to the SLL connection and they will appear again.
unsure why, possibly the setup redirects the http traffic and that causes the auth to be removed.
This may help Setting the header:
WebClient client = new WebClient();
string authInfo = this.credentials.UserName + ":" + this.credentials.Password;
authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
client.Headers["Authorization"] = "Basic " + authInfo;
static async Task<AccessToken> GetToken()
{
string clientId = "XXX";
string clientSecret = "YYY";
string credentials = String.Format("{0}:{1}", clientId, clientSecret);
using (var client = new HttpClient())
{
client.DefaultRequestHeaders.Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(Encoding.UTF8.GetBytes(credentials)));
List<KeyValuePair<string, string>> requestData = new List<KeyValuePair<string, string>>();
requestData.Add(new KeyValuePair<string, string>("grant_type", "client_credentials"));
FormUrlEncodedContent requestBody = new FormUrlEncodedContent(requestData);
var request = await client.PostAsync("https://accounts.spotify.com/api/token", requestBody);
var response = await request.Content.ReadAsStringAsync();
return JsonConvert.DeserializeObject<AccessToken>(response);
}
}
I'm looking for a way to change the audio mix of different applications in Windows (ie. Firefox audio level vs. Foobar audio level) without taking focus away from the current application. Python is my most familiar language, but I'd use another language if that'd make things easier on me. The code will be used to interface to an external HID device with some volume knobs and buttons on it. Focus needs to stay on the current window because there will be a VR game running overtop of the audio mixer, and I can't refocus on that if the script tabs away.
I've succeeded in frankensteining some older code together that uses the comtypes module, but from there I can only change left/right balance, and not application specific audio levels.
I've tried to cut my way through the relevant windows documentation on MSDN (WASAPI in particular)but it usually ends up sending me down a microsoft rabbit hole and I get in way over my head (I'm still a novice programmer at best).
Am I going about this the wrong way completely?
So the "older code" you provided is still relevant in the API on how the Windows 10 sound API works.
A great example for this type of code is currently in C#, which can be found here:
StackOverflow - c# - Controling Volume Mixer:
using System;
using System.Runtime.InteropServices;
using System.Collections.Generic;
namespace SetAppVolumne
{
class Program
{
static void Main(string[] args)
{
const string app = "Mozilla Firefox";
foreach (string name in EnumerateApplications())
{
Console.WriteLine("name:" + name);
if (name == app)
{
// display mute state & volume level (% of master)
Console.WriteLine("Mute:" + GetApplicationMute(app));
Console.WriteLine("Volume:" + GetApplicationVolume(app));
// mute the application
SetApplicationMute(app, true);
// set the volume to half of master volume (50%)
SetApplicationVolume(app, 50);
}
}
}
public static float? GetApplicationVolume(string name)
{
ISimpleAudioVolume volume = GetVolumeObject(name);
if (volume == null)
return null;
float level;
volume.GetMasterVolume(out level);
return level * 100;
}
public static bool? GetApplicationMute(string name)
{
ISimpleAudioVolume volume = GetVolumeObject(name);
if (volume == null)
return null;
bool mute;
volume.GetMute(out mute);
return mute;
}
public static void SetApplicationVolume(string name, float level)
{
ISimpleAudioVolume volume = GetVolumeObject(name);
if (volume == null)
return;
Guid guid = Guid.Empty;
volume.SetMasterVolume(level / 100, ref guid);
}
public static void SetApplicationMute(string name, bool mute)
{
ISimpleAudioVolume volume = GetVolumeObject(name);
if (volume == null)
return;
Guid guid = Guid.Empty;
volume.SetMute(mute, ref guid);
}
public static IEnumerable<string> EnumerateApplications()
{
// get the speakers (1st render + multimedia) device
IMMDeviceEnumerator deviceEnumerator = (IMMDeviceEnumerator)(new MMDeviceEnumerator());
IMMDevice speakers;
deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, out speakers);
// activate the session manager. we need the enumerator
Guid IID_IAudioSessionManager2 = typeof(IAudioSessionManager2).GUID;
object o;
speakers.Activate(ref IID_IAudioSessionManager2, 0, IntPtr.Zero, out o);
IAudioSessionManager2 mgr = (IAudioSessionManager2)o;
// enumerate sessions for on this device
IAudioSessionEnumerator sessionEnumerator;
mgr.GetSessionEnumerator(out sessionEnumerator);
int count;
sessionEnumerator.GetCount(out count);
for (int i = 0; i < count; i++)
{
IAudioSessionControl ctl;
sessionEnumerator.GetSession(i, out ctl);
string dn;
ctl.GetDisplayName(out dn);
yield return dn;
Marshal.ReleaseComObject(ctl);
}
Marshal.ReleaseComObject(sessionEnumerator);
Marshal.ReleaseComObject(mgr);
Marshal.ReleaseComObject(speakers);
Marshal.ReleaseComObject(deviceEnumerator);
}
private static ISimpleAudioVolume GetVolumeObject(string name)
{
// get the speakers (1st render + multimedia) device
IMMDeviceEnumerator deviceEnumerator = (IMMDeviceEnumerator)(new MMDeviceEnumerator());
IMMDevice speakers;
deviceEnumerator.GetDefaultAudioEndpoint(EDataFlow.eRender, ERole.eMultimedia, out speakers);
// activate the session manager. we need the enumerator
Guid IID_IAudioSessionManager2 = typeof(IAudioSessionManager2).GUID;
object o;
speakers.Activate(ref IID_IAudioSessionManager2, 0, IntPtr.Zero, out o);
IAudioSessionManager2 mgr = (IAudioSessionManager2)o;
// enumerate sessions for on this device
IAudioSessionEnumerator sessionEnumerator;
mgr.GetSessionEnumerator(out sessionEnumerator);
int count;
sessionEnumerator.GetCount(out count);
// search for an audio session with the required name
// NOTE: we could also use the process id instead of the app name (with IAudioSessionControl2)
ISimpleAudioVolume volumeControl = null;
for (int i = 0; i < count; i++)
{
IAudioSessionControl ctl;
sessionEnumerator.GetSession(i, out ctl);
string dn;
ctl.GetDisplayName(out dn);
if (string.Compare(name, dn, StringComparison.OrdinalIgnoreCase) == 0)
{
volumeControl = ctl as ISimpleAudioVolume;
break;
}
Marshal.ReleaseComObject(ctl);
}
Marshal.ReleaseComObject(sessionEnumerator);
Marshal.ReleaseComObject(mgr);
Marshal.ReleaseComObject(speakers);
Marshal.ReleaseComObject(deviceEnumerator);
return volumeControl;
}
}
[ComImport]
[Guid("BCDE0395-E52F-467C-8E3D-C4579291692E")]
internal class MMDeviceEnumerator
{
}
internal enum EDataFlow
{
eRender,
eCapture,
eAll,
EDataFlow_enum_count
}
internal enum ERole
{
eConsole,
eMultimedia,
eCommunications,
ERole_enum_count
}
[Guid("A95664D2-9614-4F35-A746-DE8DB63617E6"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface IMMDeviceEnumerator
{
int NotImpl1();
[PreserveSig]
int GetDefaultAudioEndpoint(EDataFlow dataFlow, ERole role, out IMMDevice ppDevice);
// the rest is not implemented
}
[Guid("D666063F-1587-4E43-81F1-B948E807363F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface IMMDevice
{
[PreserveSig]
int Activate(ref Guid iid, int dwClsCtx, IntPtr pActivationParams, [MarshalAs(UnmanagedType.IUnknown)] out object ppInterface);
// the rest is not implemented
}
[Guid("77AA99A0-1BD6-484F-8BC7-2C654C9A9B6F"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface IAudioSessionManager2
{
int NotImpl1();
int NotImpl2();
[PreserveSig]
int GetSessionEnumerator(out IAudioSessionEnumerator SessionEnum);
// the rest is not implemented
}
[Guid("E2F5BB11-0570-40CA-ACDD-3AA01277DEE8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface IAudioSessionEnumerator
{
[PreserveSig]
int GetCount(out int SessionCount);
[PreserveSig]
int GetSession(int SessionCount, out IAudioSessionControl Session);
}
[Guid("F4B1A599-7266-4319-A8CA-E70ACB11E8CD"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface IAudioSessionControl
{
int NotImpl1();
[PreserveSig]
int GetDisplayName([MarshalAs(UnmanagedType.LPWStr)] out string pRetVal);
// the rest is not implemented
}
[Guid("87CE5498-68D6-44E5-9215-6DA47EF883D8"), InterfaceType(ComInterfaceType.InterfaceIsIUnknown)]
internal interface ISimpleAudioVolume
{
[PreserveSig]
int SetMasterVolume(float fLevel, ref Guid EventContext);
[PreserveSig]
int GetMasterVolume(out float pfLevel);
[PreserveSig]
int SetMute(bool bMute, ref Guid EventContext);
[PreserveSig]
int GetMute(out bool pbMute);
}
}
A library that imports all the Windows Core Audio APIs COMTypes into Python that I found would be pycaw and that would be a good start if you want to learn how to port the Windows API into Python.
I want to upload files from a angularjs 2 app to my python server application.
the formData look perfect before sending it to the server. Containing name and file data.
On the other end is a Python API waiting to accept the file data. But i don't get the data. Debugger PDB get activated as the send is done by angularjs 2 app but i am missing the file data.
What could i be doing wrong?
upload.service.ts
import {Injectable} from 'angular2/core';
import {Http, Headers} from 'angular2/http';
#Injectable()
export class UploadService {
constructor(private http: Http) { }
uploader(files: any) {
let xhr = new XMLHttpRequest();
const formData = new FormData();
for(var i = 0; i < files.length; i++){
formData.append(files[i].name, files[i]);
}
var headers = new Headers();
headers.append('Content-Type', 'multipart/form-data');
xhr.onreadystatechange = function () {
if (xhr.readyState === 4) {
if (xhr.status === 200) {
resolve(JSON.parse(xhr.response))
} else {
reject(xhr.response)
}
}
}
xhr.open('POST','http://192.168.1.205:5000/zino', true)
xhr.send(formData)
}
}
python flask API debugger
As you see, the request.values are empty :(
<Request 'http://192.168.1.205:5000/zino' [POST]>
(Pdb) request.values
CombinedMultiDict([ImmutableMultiDict([]), ImmutableMultiDict([])])
This is a working example for RC angular2
import {Injectable} from '#angular/core';
import {Http, Headers, RequestOptions} from '#angular/http';
#Injectable()
export class UploadService {
constructor(private http: Http) { }
uploader(files: any) {
let xhr = new XMLHttpRequest()
const formData = new FormData()
for(var i = 0; i < files.length; i++){
formData.append(files[i].name, files[i])
}
xhr.onreadystatechange = function () {
if (xhr.readyState === 4) {
if (xhr.status === 200) {
//resolve(JSON.parse(xhr.response))
} else {
//reject(xhr.response)
}
}
}
xhr.open('POST','/server/upload-api', true)
xhr.setRequestHeader('X-Requested-With', 'XMLHttpRequest')
xhr.send(formData)
}
}
On the python side you find the files in
(Pdb) req.httprequest.files
ImmutableDict({'IMGP0269.jpg': <FileStorage: u'IMGP0269.jpg' ('image/jpeg')>, 'IMGP0270.jpg': <FileStorage: u'IMGP0270.jpg' ('image/jpeg')>})
I have an Express Node.js application, but I also have a machine learning algorithm to use in Python. Is there a way I can call Python functions from my Node.js application to make use of the power of machine learning libraries?
Easiest way I know of is to use "child_process" package which comes packaged with node.
Then you can do something like:
const spawn = require("child_process").spawn;
const pythonProcess = spawn('python',["path/to/script.py", arg1, arg2, ...]);
Then all you have to do is make sure that you import sys in your python script, and then you can access arg1 using sys.argv[1], arg2 using sys.argv[2], and so on.
To send data back to node just do the following in the python script:
print(dataToSendBack)
sys.stdout.flush()
And then node can listen for data using:
pythonProcess.stdout.on('data', (data) => {
// Do something with the data returned from python script
});
Since this allows multiple arguments to be passed to a script using spawn, you can restructure a python script so that one of the arguments decides which function to call, and the other argument gets passed to that function, etc.
Hope this was clear. Let me know if something needs clarification.
Example for people who are from Python background and want to integrate their machine learning model in the Node.js application:
It uses the child_process core module:
const express = require('express')
const app = express()
app.get('/', (req, res) => {
const { spawn } = require('child_process');
const pyProg = spawn('python', ['./../pypy.py']);
pyProg.stdout.on('data', function(data) {
console.log(data.toString());
res.write(data);
res.end('end');
});
})
app.listen(4000, () => console.log('Application listening on port 4000!'))
It doesn't require sys module in your Python script.
Below is a more modular way of performing the task using Promise:
const express = require('express')
const app = express()
let runPy = new Promise(function(success, nosuccess) {
const { spawn } = require('child_process');
const pyprog = spawn('python', ['./../pypy.py']);
pyprog.stdout.on('data', function(data) {
success(data);
});
pyprog.stderr.on('data', (data) => {
nosuccess(data);
});
});
app.get('/', (req, res) => {
res.write('welcome\n');
runPy.then(function(fromRunpy) {
console.log(fromRunpy.toString());
res.end(fromRunpy);
});
})
app.listen(4000, () => console.log('Application listening on port 4000!'))
The python-shell module by extrabacon is a simple way to run Python scripts from Node.js with basic, but efficient inter-process communication and better error handling.
Installation:
With npm:
npm install python-shell.
Or with yarn:
yarn add python-shell
Running a simple Python script:
const PythonShell = require('python-shell').PythonShell;
PythonShell.run('my_script.py', null, function (err) {
if (err) throw err;
console.log('finished');
});
Running a Python script with arguments and options:
const PythonShell = require('python-shell').PythonShell;
var options = {
mode: 'text',
pythonPath: 'path/to/python',
pythonOptions: ['-u'],
scriptPath: 'path/to/my/scripts',
args: ['value1', 'value2', 'value3']
};
PythonShell.run('my_script.py', options, function (err, results) {
if (err)
throw err;
// Results is an array consisting of messages collected during execution
console.log('results: %j', results);
});
For the full documentation and source code, check out https://github.com/extrabacon/python-shell
You can now use RPC libraries that support Python and Javascript such as zerorpc
From their front page:
Node.js Client
var zerorpc = require("zerorpc");
var client = new zerorpc.Client();
client.connect("tcp://127.0.0.1:4242");
client.invoke("hello", "RPC", function(error, res, more) {
console.log(res);
});
Python Server
import zerorpc
class HelloRPC(object):
def hello(self, name):
return "Hello, %s" % name
s = zerorpc.Server(HelloRPC())
s.bind("tcp://0.0.0.0:4242")
s.run()
Many of the examples are years out of date and involve complex setup. You can give JSPyBridge/pythonia a try (full disclosure: I'm the author). It's vanilla JS that lets you operate on foreign Python objects as if they existed in JS. In fact, it does interoperability so Python code can in return call JS through callbacks and passed functions.
numpy + matplotlib example, with the ES6 import system:
import { py, python } from 'pythonia'
const np = await python('numpy')
const plot = await python('matplotlib.pyplot')
// Fixing random state for reproducibility
await np.random.seed(19680801)
const [mu, sigma] = [100, 15]
// Inline expression evaluation for operator overloading
const x = await py`${mu} + ${sigma} * ${np.random.randn(10000)}`
// the histogram of the data
const [n, bins, patches] = await plot.hist$(x, 50, { density: true, facecolor: 'g', alpha: 0.75 })
console.log('Distribution', await n) // Always await for all Python access
await plot.show()
python.exit()
Through CommonJS (without top level await):
const { py, python } = require('pythonia')
async function main() {
const np = await python('numpy')
const plot = await python('matplotlib.pyplot')
...
// the rest of the code
}
main().then(() => python.exit()) // If you don't call this, the process won't quit by itself.
Most of previous answers call the success of the promise in the on("data"), it is not the proper way to do it because if you receive a lot of data you will only get the first part. Instead you have to do it on the end event.
const { spawn } = require('child_process');
const pythonDir = (__dirname + "/../pythonCode/"); // Path of python script folder
const python = pythonDir + "pythonEnv/bin/python"; // Path of the Python interpreter
/** remove warning that you don't care about */
function cleanWarning(error) {
return error.replace(/Detector is not able to detect the language reliably.\n/g,"");
}
function callPython(scriptName, args) {
return new Promise(function(success, reject) {
const script = pythonDir + scriptName;
const pyArgs = [script, JSON.stringify(args) ]
const pyprog = spawn(python, pyArgs );
let result = "";
let resultError = "";
pyprog.stdout.on('data', function(data) {
result += data.toString();
});
pyprog.stderr.on('data', (data) => {
resultError += cleanWarning(data.toString());
});
pyprog.stdout.on("end", function(){
if(resultError == "") {
success(JSON.parse(result));
}else{
console.error(`Python error, you can reproduce the error with: \n${python} ${script} ${pyArgs.join(" ")}`);
const error = new Error(resultError);
console.error(error);
reject(resultError);
}
})
});
}
module.exports.callPython = callPython;
Call:
const pythonCaller = require("../core/pythonCaller");
const result = await pythonCaller.callPython("preprocessorSentiment.py", {"thekeyYouwant": value});
python:
try:
argu = json.loads(sys.argv[1])
except:
raise Exception("error while loading argument")
I'm on node 10 and child process 1.0.2. The data from python is a byte array and has to be converted. Just another quick example of making a http request in python.
node
const process = spawn("python", ["services/request.py", "https://www.google.com"])
return new Promise((resolve, reject) =>{
process.stdout.on("data", data =>{
resolve(data.toString()); // <------------ by default converts to utf-8
})
process.stderr.on("data", reject)
})
request.py
import urllib.request
import sys
def karl_morrison_is_a_pedant():
response = urllib.request.urlopen(sys.argv[1])
html = response.read()
print(html)
sys.stdout.flush()
karl_morrison_is_a_pedant()
p.s. not a contrived example since node's http module doesn't load a few requests I need to make
You could take your python, transpile it, and then call it as if it were javascript. I have done this succesfully for screeps and even got it to run in the browser a la brython.
The Boa is good for your needs, see the example which extends Python tensorflow keras.Sequential class in JavaScript.
const fs = require('fs');
const boa = require('#pipcook/boa');
const { tuple, enumerate } = boa.builtins();
const tf = boa.import('tensorflow');
const tfds = boa.import('tensorflow_datasets');
const { keras } = tf;
const { layers } = keras;
const [
[ train_data, test_data ],
info
] = tfds.load('imdb_reviews/subwords8k', boa.kwargs({
split: tuple([ tfds.Split.TRAIN, tfds.Split.TEST ]),
with_info: true,
as_supervised: true
}));
const encoder = info.features['text'].encoder;
const padded_shapes = tuple([
[ null ], tuple([])
]);
const train_batches = train_data.shuffle(1000)
.padded_batch(10, boa.kwargs({ padded_shapes }));
const test_batches = test_data.shuffle(1000)
.padded_batch(10, boa.kwargs({ padded_shapes }));
const embedding_dim = 16;
const model = keras.Sequential([
layers.Embedding(encoder.vocab_size, embedding_dim),
layers.GlobalAveragePooling1D(),
layers.Dense(16, boa.kwargs({ activation: 'relu' })),
layers.Dense(1, boa.kwargs({ activation: 'sigmoid' }))
]);
model.summary();
model.compile(boa.kwargs({
optimizer: 'adam',
loss: 'binary_crossentropy',
metrics: [ 'accuracy' ]
}));
The complete example is at: https://github.com/alibaba/pipcook/blob/master/example/boa/tf2/word-embedding.js
I used Boa in another project Pipcook, which is to address the machine learning problems for JavaScript developers, we implemented ML/DL models upon the Python ecosystem(tensorflow,keras,pytorch) by the boa library.
/*eslint-env es6*/
/*global require*/
/*global console*/
var express = require('express');
var app = express();
// Creates a server which runs on port 3000 and
// can be accessed through localhost:3000
app.listen(3000, function() {
console.log('server running on port 3000');
} )
app.get('/name', function(req, res) {
console.log('Running');
// Use child_process.spawn method from
// child_process module and assign it
// to variable spawn
var spawn = require("child_process").spawn;
// Parameters passed in spawn -
// 1. type_of_script
// 2. list containing Path of the script
// and arguments for the script
// E.g : http://localhost:3000/name?firstname=Levente
var process = spawn('python',['apiTest.py',
req.query.firstname]);
// Takes stdout data from script which executed
// with arguments and send this data to res object
var output = '';
process.stdout.on('data', function(data) {
console.log("Sending Info")
res.end(data.toString('utf8'));
});
console.log(output);
});
This worked for me. Your python.exe must be added to you path variables for this code snippet. Also, make sure your python script is in your project folder.
const util = require('util');
const exec = util.promisify(require('child_process').exec);
function runPythonFile() {
const { stdout, stderr } = await exec('py ./path_to_python_file -s asdf -d pqrs');
if (stdout) { // do something }
if (stderr) { // do something }
}
For more information visit official Nodejs child process page: https://nodejs.org/api/child_process.html#child_processexeccommand-options-callback
you can check out my package on npm
https://www.npmjs.com/package/#guydev/native-python
it provides a very simple and powerful way to run python functions from node
import { runFunction } from '#guydev/native-python'
const example = async () => {
const input = [1,[1,2,3],{'foo':'bar'}]
const { error, data } = await runFunction('/path/to/file.py','hello_world', '/path/to/python', input)
// error will be null if no error occured.
if (error) {
console.log('Error: ', error)
}
else {
console.log('Success: ', data)
// prints data or null if function has no return value
}
}
python module
# module: file.py
def hello_world(a,b,c):
print( type(a), a)
# <class 'int'>, 1
print(type(b),b)
# <class 'list'>, [1,2,3]
print(type(c),c)
# <class 'dict'>, {'foo':'bar'}