We Keep Coding

Sending opencv image along with additional data to Flask Server

I am currently able to send OpenCV image frames to my Flask Server using the following code
def sendtoserver(frame):
imencoded = cv2.imencode(".jpg", frame)[1]
headers = {"Content-type": "text/plain"}
try:
conn.request("POST", "/", imencoded.tostring(), headers)
response = conn.getresponse()
except conn.timeout as e:
print("timeout")
return response
But I want to send a unique_id along with the frame I tried combining the frame and the id using JSON but getting following error TypeError: Object of type 'bytes' is not JSON serializable does anybody have any idea how I can send some additional data along with the frame to the server.
UPDATED:
json format code
def sendtoserver(frame):
imencoded = cv2.imencode(".jpg", frame)[1]
data = {"uid" : "23", "frame" : imencoded.tostring()}
headers = {"Content-type": "application/json"}
try:
conn.request("POST", "/", json.dumps(data), headers)
response = conn.getresponse()
except conn.timeout as e:
print("timeout")
return response

I have actually solved the query by using the Python requests module instead of the http.client module and have done the following changes to my above code.
import requests
def sendtoserver(frame):
imencoded = cv2.imencode(".jpg", frame)[1]
file = {'file': ('image.jpg', imencoded.tostring(), 'image/jpeg', {'Expires': '0'})}
data = {"id" : "2345AB"}
response = requests.post("http://127.0.0.1/my-script/", files=file, data=data, timeout=5)
return response
As I was trying to send a multipart/form-data and requests module has the ability to send both files and data in a single request.

You can try encoding your image in base64 string
import base64
with open("image.jpg", "rb") as image_file:
encoded_string = base64.b64encode(image_file.read())
And send it as a normal string.

As others suggested base64 encoding might be a good solution, however if you can't or don't want to, you could add a custom header to the request, such as
headers = {"X-my-custom-header": "uniquevalue"}
Then on the flask side:
unique_value = request.headers.get('X-my-custom-header')
or
unique_value = request.headers['X-my-custom-header']
That way you avoid the overhead of processing your image data again (if that matters) and you can generate a unique id for each frame with something like the python uuid module.
Hope that helps

DELETE Request in Python "requests" module not working with body

I have been using this function to handle http requests with no problems:
def do_request(self, method, url, **kwargs):
params = kwargs.get('params', None)
headers = kwargs.get('headers', None)
payload = kwargs.get('data', None)
request_method = {'GET':requests.get, 'POST': requests.post, 'PUT': requests.put, 'DELETE': requests.delete}
request_url = url
req = request_method[method]
try:
res = req(request_url, headers=headers, params=params, data=json.dumps(payload))
except (requests.exceptions.ConnectionError, requests.exceptions.RequestException) as e:
data = {'has_error':True, 'error_message':e.message}
return data
try:
data = res.json()
data.update({'has_error':False, 'error_message':''})
except ValueError as e:
msg = "Cannot read response, %s" %(e.message)
data = {'has_error':True, 'error_message':msg}
if not res.ok:
msg = "Response not ok"
data.update({'has_error':True, 'error_message':msg})
if res.status_code >= 400:
msg = 'Error code: ' + str(res.status_code) + '\n' + data['errorCode']
data.update({'has_error':True, 'error_message': msg})
return data
When I have to do a DELETE request without body entity I have no problems but when I try to add one (when required by the server) I get an error message from the server telling that the body cannot be null as if no body has been sent. Any ideas why this might be happening? I'm using requests module and python 2.7.12. As far as I know data can be send in a DELETE request. Thanks!

There are problems with some clients and some servers when DELETE includes entity body: Is an entity body allowed for an HTTP DELETE request? for example & lots of search results.
Some servers (apparently) convert the DELETE into a POST, others simply perform the DELETE but drop the body. In your case, you've investigated that indeed, the body of a DELETE is dropped by the server & it has been suggested that you change the DELETE to POST.

Mmm... I can send a DELETE with body with Postman and works OK. But I cant get the same result with Requests 2.17.3
This is a issue related to Requests

python urllib2 post data

I need to pass some data to the following urllib2 request,
handler = urllib2.HTTPSHandler()
opener = urllib2.build_opener(handler)
request = urllib2.Request(url)
request.add_header("Accept",'application/*+xml;version=5.5')
request.add_header("x-vcloud-authorization",authtoken)
request.get_method = lambda: method
data = "some XML request"
try:
connection = opener.open(request)
except urllib2.HTTPError,e:
connection = e
if connection.code == 200:
data = connection.read()
#print "Data from Entity"
#print "Data :", data
else:
print "ERROR", connection.code
sys.exit(1)
will
connection = opener.open(request, data)
work? if not how can I pass data to the request?
UPDATE:
I think i can pass it this way
request = urllib2.Request(url, data="some data")

You can use the method urllib2.Request.add_data:
request.add_header('xxxx', 'vvvv')
request.add_data('some XML request')
opener.open(request)
This converts it to a POST request.

import urllib2
import json
# Whatever structure you need to send goes here:
jdata = json.dumps({"username":"...", "password":"..."})
urllib2.urlopen("http://www.example.com/", jdata)
But i recommend to you use requests is the best option to handle http calls.

Error in Json request :{"jsonrpc":"2.0","id":44,"error":{"code":-32603,"message":"No such service method"}}

I'm trying to create a HTTPSConnection to this address: "android-review.googlesource.com" and send a json request.
This address: "android-review.googlesource.com" is for Gerrit code review system which uses REST API. You can find more information about the Gerrit Rest-api here:
https://gerrit-review.googlesource.com/Documentation/rest-api.html.
Each review in Gerrit code review system is related to a change request which I tried to get the change request information with a json request. This is the url and request:
url = "/gerrit_ui/rpc/ChangeDetailService"
req = {"jsonrpc" : "2.0",
"method": "changeDetail",
"params": [{"id": id}],
"id": 44
}
you can find the complete code here:
import socket, sys
import httplib
import pyodbc
import json
import types
import datetime
import urllib2
import os
import logging
import re, time
def GetRequestOrCached( url, method, data, filename):
path = os.path.join("json", filename)
if not os.path.exists(path):
data = MakeRequest(url, method, data)
time.sleep(1)
data = data.replace(")]}'", "")
f = open(path, "w")
f.write(data)
f.close()
return open(path).read()
def MakeRequest(url, method, data, port=443):
successful = False
while not successful:
try:
conn = httplib.HTTPSConnection("android-review.googlesource.com", port)
headers = {"Accept": "application/json,application/jsonrequest",
"Content-Type": "application/json; charset=UTF-8",
"Content-Length": len(data)}
conn.request(method, url, data, headers)
conn.set_debuglevel(1)
successful = True
except socket.error as err:
# this means a socket timeout
if err.errno != 10060:
raise(err)
else:
print err.errno, str(err)
print "sleep for 1 minute before retrying"
time.sleep(60)
resp = conn.getresponse()
if resp.status != 200:
raise GerritDataException("Got status code %d for request to %s" % (resp.status, url))
return resp.read()
#-------------------------------------------------
id=51750
filename = "%d-ChangeDetails.json" % id
url = "/gerrit_ui/rpc/ChangeDetailService"
req = {"jsonrpc" : "2.0",
"method": "changeDetail",
"params": [{"id": id}],
"id": 44
}
data = GetRequestOrCached(url, "POST", json.dumps(req), filename)
print json.loads(data)
In the code id means review id which can be a number between 1 and 51750, but not necessary all of these ids exist in the system so different numbers can be tried to see finally which one responds. For example these three ids definitely exist: 51750-51743-51742. I tried for these numbers but for all of them I got the same error:
"{"jsonrpc":"2.0","id":44,"error":{"code":-32603,"message":"No such service method"}}"
so I guess there is something wrong with code.

Why are you using url = "/gerrit_ui/rpc/ChangeDetailService"? That isn't in your linked REST documentation at all. I believe this is an older internal API which is no longer supported. I'm also not sure why your method is POST.
Instead, something like this works just fine for me:
curl "https://android-review.googlesource.com/changes/?q=51750"

VCloud Director Org user authentication for RestAPI in python

I have VMware setup for testing. I create one user abc/abc123 to access the Org url "http://localhost/cloud/org/MyOrg". I want to access the RestAPI of the VCloud. I tried with RestClient plugin in firefox. Its working fine.
Now I tried with python code.
url = 'https://localhost/api/sessions/'
req = urllib2.Request(url)
base64string = base64.encodestring('%s:%s' % ('abc#MyOrg', 'abc123'))[:-1]
authheader = "Basic %s" % base64string
req.add_header("Authorization", authheader)
req.add_header("Accept", 'application/*+xml;version=1.5')
f = urllib2.urlopen(req)
data = f.read()
print(data)
This is the code i get from stackoverflow. But for my example its give "urllib2.HTTPError: HTTP Error 403: Forbidden" Error.
I also tried HTTP authentication for the same.

After doing some googling I found the solution from the post https://stackoverflow.com/a/6348729/243031. I change the code for my usability. I am posting the answer because if some one has same error then he will get the answer directly.
My change code is:
import urllib2
import base64
# make a string with the request type in it:
method = "POST"
# create a handler. you can specify different handlers here (file uploads etc)
# but we go for the default
handler = urllib2.HTTPSHandler()
# create an openerdirector instance
opener = urllib2.build_opener(handler)
# build a request
url = 'https://localhost/api/sessions'
request = urllib2.Request(url)
# add any other information you want
base64string = base64.encodestring('%s:%s' % ('abc#MyOrg', 'abc123'))[:-1]
authheader = "Basic %s" % base64string
request.add_header("Authorization", authheader)
request.add_header("Accept",'application/*+xml;version=1.5')
# overload the get method function with a small anonymous function...
request.get_method = lambda: method
# try it; don't forget to catch the result
try:
connection = opener.open(request)
except urllib2.HTTPError,e:
connection = e
# check. Substitute with appropriate HTTP code.
if connection.code == 200:
data = connection.read()
print "Data :", data
else:
print "ERRROR", connection.code
Hope this will help some one who want to send POST request without the data.