├── .gitignore
├── README.md
├── requirements.txt
└── streaming.py


/.gitignore:
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  1 | # Byte-compiled / optimized / DLL files
  2 | __pycache__/
  3 | *.py[cod]
  4 | *$py.class
  5 | 
  6 | # C extensions
  7 | *.so
  8 | 
  9 | # Distribution / packaging
 10 | .Python
 11 | env/
 12 | build/
 13 | develop-eggs/
 14 | dist/
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 18 | lib/
 19 | lib64/
 20 | parts/
 21 | sdist/
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 23 | wheels/
 24 | *.egg-info/
 25 | .installed.cfg
 26 | *.egg
 27 | 
 28 | # PyInstaller
 29 | #  Usually these files are written by a python script from a template
 30 | #  before PyInstaller builds the exe, so as to inject date/other infos into it.
 31 | *.manifest
 32 | *.spec
 33 | 
 34 | # Installer logs
 35 | pip-log.txt
 36 | pip-delete-this-directory.txt
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 38 | # Unit test / coverage reports
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 46 | *.cover
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 48 | 
 49 | # Translations
 50 | *.mo
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 52 | 
 53 | # Django stuff:
 54 | *.log
 55 | local_settings.py
 56 | 
 57 | # Flask stuff:
 58 | instance/
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 73 | # pyenv
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 76 | # celery beat schedule file
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 80 | *.sage.py
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 85 | # virtualenv
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 97 | # mkdocs documentation
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 99 | 
100 | # mypy
101 | .mypy_cache/
102 | 


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/README.md:
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 1 | # python_flask_file_streaming
 2 | Example of streaming files for upload/download and both (proxy) in Python Flask.
 3 | 
 4 | For more detailed explanation see my post: http://izmailoff.github.io/web/flask-file-streaming.
 5 | 
 6 | # Quick Start
 7 | Clone this repo:
 8 | 
 9 |     git clone git@github.com:izmailoff/python_flask_file_streaming.git
10 | 
11 | Navigate to the project:
12 | 
13 |     cd python_flask_file_streaming
14 | 
15 | Create a virtual environment. One option is:
16 | 
17 |     python3.6 -m venv env
18 | 
19 | Activate the environment:
20 | 
21 |     source env/bin/activate
22 | 
23 | Install all dependencies (flask, requests):
24 | 
25 |     pip install -r requirements.txt
26 | 
27 | Edit this line:
28 | 
29 |     resp = requests.post('http://destination_host/upload_api', files={'file': request.stream})
30 | 
31 | in `streaming.py` to set correct upload host, and optionally adjust other parameters of the `post` request. See the comments in the code for more details.
32 | 
33 | Start the application:
34 | 
35 |     python streaming.py
36 | 
37 | Upload a file to one of the APIs. For example:
38 | 
39 |     curl -F "file=@any_file_binary_or_text.ext" http://127.0.0.1:5000/proxy
40 | 
41 | Profit.
42 | 


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/requirements.txt:
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1 | Flask
2 | requests
3 | 


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/streaming.py:
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 1 | from flask import Flask
 2 | from flask import Response
 3 | from flask import stream_with_context
 4 | import requests
 5 | from flask import request
 6 | 
 7 | app = Flask(__name__)
 8 | 
 9 | 
10 | # Upload file as stream to a file.
11 | @app.route("/upload", methods=["POST"])
12 | def upload():
13 |     with open("/tmp/output_file", "bw") as f:
14 |         chunk_size = 4096
15 |         while True:
16 |             chunk = request.stream.read(chunk_size)
17 |             if len(chunk) == 0:
18 |                 return
19 |             f.write(chunk)
20 | 
21 | 
22 | # Download from provided URL.
23 | @app.route('/<path:url>')
24 | def download(url):
25 |     req = requests.get(url, stream=True)
26 |     return Response(stream_with_context(req.iter_content()), content_type=req.headers['content-type'])
27 | 
28 | 
29 | # Proxy uploaded files as stream to another web API without saving them to disk or holding them in memory.
30 | # This example uses multipart form data upload for both this API and destination API.
31 | #
32 | # Test this endpoint with:
33 | # curl -F "file=@some_binary_file.pdf" http://127.0.0.1:5000/proxy
34 | @app.route("/proxy", methods=["POST"])
35 | def proxy():
36 |     # use data=... or files=..., etc in the call below - this affects the way data is POSTed: form-encoded for `data`,
37 |     # multipart encoding for `files`. See the code/docs for more details here:
38 |     # https://github.com/requests/requests/blob/master/requests/api.py#L16
39 |     resp = requests.post('http://destination_host/upload_api', files={'file': request.stream})
40 |     return resp.text, resp.status_code
41 | 
42 | 
43 | if __name__ == '__main__':
44 |     app.run()
45 | 


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