How to get multiple images from Flask request object at once in case of Content-Type:multipart/form-data?

I’m supposed to get multiple image files from the requests, but I can’t find a way to split a byte string request.files[key].read() properly to make np.ndarrays out of them.

Answer

files[key] gives only one object which has name=key in HTML, and .read() gives data only for this single file. So there is no need to split it.

If you have many files with name=key then you need files.getlist(key) to get list with all files and next use for-loop to read every file separatelly.

for item in request.files.getlist('image'):
    data = item.read()
    print('len:', len(data))

---

Minimal working example:

from flask import Flask, request, render_template_string

app = Flask(__name__)

@app.route('/', methods=['GET', 'POST'])
def image():
    if request.method == "POST":
        #print('args :', request.args)
        #print('form :', request.form)
        #print('json :', request.json)
        #print('files:', request.files)
        print(request.files['image'])
        print(request.files.getlist('image'))
        
        for item in request.files.getlist('image'):
            data = item.read()
            print('len:', len(data))
        
    return render_template_string('''
<form method="POST" enctype="multipart/form-data">
Single image: <input type="file" name="image"/></br>
Multiple images: <input type="file" name="image" multiple/></br>
<button type="submit" name="button" value="send">Send</button>
</form>
''')

if __name__ == '__main__':
    #app.debug = True 
    app.run()