how to send multifile by requests module to FastAPI?

[jbc0708]

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Example Code

[Server]
from fastapi import FastAPI,  File, UploadFile

app = FastAPI()

@app.post("/single")
async def check(file: bytes = File() ):
    print(len(file))
    return {"state": 200}

@app.post("/multi")
async def check(files: list[bytes] = File()  ):
    for file in files:
        print(len(file))
    return {"state": 200}

[Client]
import requests

files1 = {  "file": open("images/4_1_1.jpg", "rb") }
files2 = {
        "file1": open("images/4_1_1.jpg", "rb"),
        "file2": open("images/4_1_2.jpg", "rb")
}

r = requests.post("http://127.0.0.1:8000/single", files=files1)
result = r.json()
print(result["state"])

r = requests.post("http://127.0.0.1:8000/multi", files=files2)
result = r.json()
print(result["state"])

I have problem about transfer multi files from client to Server..

Description

Single file send dont have issue..
but multi file send always have issue..

result of single file send:
Server: INFO: 127.0.0.1:54755 - "POST /single HTTP/1.1" 200 OK
Client: 200

result of multi file send:
Server: INFO: 127.0.0.1:54761 - "POST /multi HTTP/1.1" 422 Unprocessable Entity
Client: KeyError: "state"

How can i fix it..? please help me

Operating System

macOS

Operating System Details

No response

FastAPI Version

0.78.0

Python Version

3.10.4

Additional Context

No response

[arunppsg]

From the request files docs, the multifile upload argument should probably be like this:

from typing import List

@app.post("/multi")
async def check(files: List[UploadFile]):
    for file in files:
        print(len(file))
    return {"state": 200}

[jbc0708]

From the request files docs, the multifile upload argument should probably be like this:

from typing import List

@app.post("/multi")
async def check(files: List[UploadFile]):
    for file in files:
        print(len(file))
    return {"state": 200}

Your code for pytho3.6 and above.. right?
But I use python3.10 ...
and I know that instant of UploadFile can't use len() method...

[JarroVGIT]

The main reason you have a problem is because you are sending with two different names. Multiple files in FastAPI are received as a List of either bytes or UploadFile objects. I would recommend the latter, as the first is pure in-memory and the latter actually gives you greater control and allows for larger files. As the parameter in your path operation function is called files, it can't handle the post you are making (mimicking form-input with names file1 and file2, used as keys in your dictionary when making the request).

I have created a working sample for you here: https://github.com/JarroVGIT/fastapi-github-issues/tree/master/4992

Note that I use UploadFile in my FastAPI app. In my client, I give a list of tuples like so:
(form-input-name, (filename, filehandler, file_info))

The app:

from fastapi import FastAPI,  File, UploadFile
import uvicorn

app = FastAPI()

@app.post("/multi")
async def check_multi_files(files: list[UploadFile]):
    return {"filenames": [file.filename for file in files]}

if __name__ == "__main__":
    uvicorn.run(app, host="0.0.0.0", port=8000)

The client:

import requests

url = 'http://localhost:8000/multi'
multiple_files = [('files', ('file1.txt', open('files/file1.txt', 'rb'), 'text/plain')),
                      ('files', ('file2.txt', open('files/file2.txt', 'rb'), 'text/plain'))]
r = requests.post(url, files=multiple_files)
print(r.text)

Hope this clarifies.

[mkmkmkmkmkmkmkmkmkmkmk]

1. My front-end code sends the request code like this
   
2. The backend code looks like this：
   
3. console.log(fd.getAll("file"))输出如下：
   
   4.Why does the 422 error occur when accessing this interface '/v1/uploadFiles/'? How should I receive this fd request data on the backend? How should I modify it？
   

（vesion: fastapi： 0.109.0 python:3.11.5）

[jbc0708]

@app.post("/multi")
async def check_multi_files(files: list[UploadFile]):
    return {"filenames": [file.filename for file in files]}

Hi JarroVGIT~!. First of all, Thank you.
I have coded as per your suggestion and succeeded in uploading multi-files.
Thank you~!

[bengabp]

I want to create a route to upload multiple files where each file has a name and description field like saving a list of identified documents for a user, how will i write my fastapi route to handle all files and get their names and descriptions correctly;

in a json payload it could look like this

{
	"files":[
		{"name": "Residential document": "description":"This is a residential document", "file": "some bytes data"},
		{"name": "Residential document": "description":"This is a residential document", "file": "some bytes data"},
		{"name": "Residential document": "description":"This is a residential document", "file": "some bytes data"},

	]
}

I know i can create one route to this this for a single file , but it would mean that the client would need to call my api route multiple times in a row. Is this a good design pattern or is there a better way

[iudeen]

This doesn't seem like standard multipart file upload request.

You can always create your own request with normal post request to meet your needs.