I've downloaded a small .mp3 file from the net using Python's requests module, like this:
file_on_disk = open(filename, 'wb')
write(downloaded_file.content)
file_on_disk.close()
Now it works fine on the disk as an MP3 file should. However, I'd like to play it using python-vlc's MediaPlayer while it's still not written to disk, i.e. from memory. However, this doesn't work:
vlc.MediaPlayer(downloaded_file.content).play()
I get a TypeError: a bytes-like object is required, not 'str' message. I checked the type of the content and type(downloaded_file.content) identifies it as <class 'bytes'>, not str. The same MediaPlayer nicely plays the file once it's saved to the disk. What am I missing here, and how can I convert the file in-memory to a format that vlc.MediaPlayer is able to play?
(I'm a beginner so the answer might be obvious, but it keeps eluding me.)
edit: my full code is actually:
import requests, vlc
downloaded_file = requests.get('https://cdn.duden.de/_media_/audio/ID4111733_460321137.mp3')
from vlc import MediaPlayer
MediaPlayer(downloaded_file.content).play()
Check out this possibly related question, you need to create a vlc Instance.
Related
I'm trying to retrieve pickle data I have uploaded to an openstack object storage using openstacksdk's connection.get_object(container,object), I get a response from it, however the file body is a string, I can even save it to file with the outfile option without issues. However I would like to be able to work with it directly without having to resort to save it to file first and then loading it into pickle.
Simply using pickle's load and loads doesn't work as neither takes string objects. Is there another way to retrieve the data so I can work with the pickled data directly or is there some way to parse to string/set a config parameter on get_object()?
If you are using Python 3 - pickle expects a bytes-like object. The load method takes a file path, and relies on the file type to handle the providing of bytes back into pickle. When you use the loads method you need to provide it a bytes-like object, not a string, so you will need to convert the string to bytes.
Best way to convert string to bytes in Python 3?
EDIT:
I found the solution, for pickled objects or any other files retrieved from openstack with openstacksdk, there are a few ways of dealing with the data without resorting to disk.
First my implemented solution was to use openstack's connection method get_object_raw:
conn = connection(foo,bar, arg**)
pickle.loads(conn.get_object_raw('containerName', 'ObjectName').content)
.get_object_raw returns a response request object with the attribute content which is the binary file content which is the pickle content one can load with pickle.
You could also create a temporary in-memory file with io.BytesIO, and using it as the outfile argument in get_object from the connection object.
So I am writing a basic multipurpose script which uses json to import a dictionary from a file but for some reason it doesn't save properly. I've looked all over and can't find anything relating to my exact problem.
Here is my code:
import json
dicti = json.loads(open('database.db'))
print(str(dicti))
But then I get this error:
TypeError: JSON object must be str, not TextIOWrapper.
So does anyone have any ideas on what the problem is? Thanks in Advance.
Note: Currently the file only has inside it:
{}
You want json.load for loading a file. json.loads is for loading from a string.
i've a issue with Python.
My case: i've a gzipped file from a partner platform (i.e. h..p//....namesite.../xxx)
If i click the link from my browser, it will download a file like (i.e. namefile.xml.gz).
So... if i read this file with python i can decompress and read it.
Code:
content = gzip.open(namefile.xml.gz,'rb')
print content.read()
But i can't if i try to read the file from remote source.
From remote file i can read only the encoded string, but not decoded it.
Code:
response = urllib2.urlopen(url)
encoded =response.read()
print encoded
With this code i can read the string encoded... but i can't decoded it with gzip or lzip.
Any advices?
Thanks a lot
Unfortunately the method #Aya suggests does not work, since GzipFile extensively uses seek method of the file object (not supported by response).
So you have basically two options:
Read the contents of the remote file into io.StringIO, and pass the object into gzip.GzipFile (if the file is small)
download the file into a temporary file on disk, and use gzip.open
There is another option (which requires some coding) - to implement your own reader using zlib module. It is rather easy, but you will need to know about a magic constant (How can I decompress a gzip stream with zlib?).
If you use Python 3.2 or later the bug in GzipFile (requiring tell support) is fixed, but they apparently aren't going to backport the fix to Python 2.x
For Python v3.2 or later, you can use the gzip.GzipFile class to wrap the file object returned by urllib2.urlopen(), with something like this...
import urllib2
import gzip
response = urllib2.urlopen(url)
gunzip_response = gzip.GzipFile(fileobj=response)
content = gunzip_response.read()
print content
...which will transparently decompress the response stream as you read it.
I would like to know a very basic thing of Python programming as I am a very basic programmer right now): how can I save a result (either a list, a string, or whatever) to a file in Python?
I've been searching a lot, but I couldn't find any good answer to this.
I was thinking about the ".write ()" method, but (for instance) it seems not working with strings, neither I know what it is supposed to do though.
So, my situation is that I have binary fils, which I would like to edit, therefore I found easy to convert them to strings, modify them, and now I'd like to save them i) back to binary files (jpegs images) and ii) in the folder I want.
How would I do that? Please I need some help.
UPDATE
Here is the script I'm trying to run:
import os, sys
newpath= r'C:/Users/Umberto/Desktop/temporary'
if not os.path.exists (newpath):
os.makedirs (newpath)
data= open ('C:/Users/Umberto/Desktop/Prove_Script/Varie/_BR_Browse.001_2065642654_1.BINARY', 'rb+')
edit_data= str (data.read () )
out_dir= os.path.join (newpath, 'feed', 'address')
data.close ()
# do my edits in a secon time...
edit_data.write (newpath)
edit_data.close ()
The error I get is:
AttributeError: 'str' object has no attribute 'write'
UPDATE_2
I tried to use pickle module to serialize my binary file, modify it and save it at the end, but still not getting it to work... This is what I've been trying so far:
import cPickle as pickle
binary= open ('C:\Users\Umberto\Desktop\Prove_Script\Varie\_BR_Browse.001_2065642654_1.BINARY', 'rb')
out= open ('C:\Users\Umberto\Desktop\Prove_Script\Varie\preview.txt', 'wb')
pickle.dump (binary, out, 1)
TypeError Traceback (most recent call last)
<ipython-input-6-981b17a6ad99> in <module>()
----> 1 pprint.pprint (pickle.dump (binary, out, 1))
C:\Python27\ArcGIS10.1\lib\copy_reg.pyc in _reduce_ex(self, proto)
68 else:
69 if base is self.__class__:
---> 70 raise TypeError, "can't pickle %s objects" % base.__name__
71 state = base(self)
72 args = (self.__class__, base, state)
TypeError: can't pickle file objects
Another thing I didn't get is that if I am supposed to create a file to poit to (in my case I had to create "out", otherwise I wouldn't have the right arguments for the pickle method) or it's not necessary.
Hope I'm getting close to the solution.
P.S.: I tried also with pickle.dumps (), not achieving a nicer result though...
If you're opening a binary file and saving another binary file you could do something like this:
with open('file.jpg', 'rb') as jpgFile:
contents = jpgFile.read()
contents = (some operations here)
with open('file2.jpg', 'wb') as jpgFile:
jpgFile.write(contents)
Some comments:
'rb' and 'wb' means read and write in binary mode respectively. More info on why 'b' is recommended when working with binary files here.
Python's with statement takes care of closing the file when exiting the block.
If you need to save lists, strings or other objects, and retrieving them later, use pickle as others pointed out.
You can use standard python module named "pickle".
You can read about it here: pickle documentation
Read and write any data structure will be very easy
pickle.dump(obj, file_handler) # for serialize object to file
pickle.load(file) # for deserialize from file
or you can serialize to string: pickle.dumps(..) and load from it: pickle.loads(...)
I got a file that contains a data structure with test results from a Windows user. He created this file using the pickle.dump command. On Ubuntu, I tried to load this test results with the following program:
import pickle
import my_module
f = open('results', 'r')
print pickle.load(f)
f.close()
But I get an error inside pickle module that no module named "my_module".
May the problem be due to corruption in the file, or maybe moving from Widows to Linux is the couse?
The problem lies in pickle's way of handling newline characters. Some of the line feed characters cripple module names in dumped / loaded data.
Storing and loading files in binary mode may help, but I was having trouble with them too. After a long time reading docs and searching I found that pickle handles several different "protocols" for storing data and due to backward compatibility it uses the oldest one: protocol 0 - the original ASCII protocol.
User can select modern protocol by specifing the protocol keyword while storing data in dump file, something like this:
pickle.dump(someObj, open("dumpFile.dmp", 'wb'), protocol=2)
or, by choosing the highest protocol available (currently 2)
pickle.dump(someObj, open("dumpFile.dmp", 'wb'), protocol=pickle.HIGHEST_PROTOCOL)
Protocol version is stored in dump file, so Load() function handles it automaticaly.
Regards
You should open the pickled file in binary mode, especially if you are using pickle on different platforms. See this and this questions for an explanation.