Unable to send POST request from postman to API made using Flask

Question

Hi I am new to writing web APIs in python. And my understanding of REST is limited

I have a simple Flask API that takes in a python dict {'pdf':pdf_as_bytes, 'filename':string}

The below is my server script:

@app.route("/predict", methods=["POST"])
def predict():
    data = {"success": False}
    if flask.request.method == "POST":
        pdf = flask.request.files["pdf"].read()
        filename = flask.request.files["filename"].read().decode("utf-8")
        assert isinstance(filename, str), "Got {}".format(type(filename))
        assert isinstance(pdf, bytes), "Got {}".format(type(pdf))
        # further processing happens and returns a json

This works as intended when I write a python client as follows:

import requests
import os

ip = "localhost" 
port = 8605 

url = "http://{}:{}/predict".format(ip,port)

path_to_pdf = "./617339931.pdf"

with open(path_to_pdf, "rb") as f:
    pdf = f.read() # pdf is a bytes

# the payload must have the following fields: "pdf": bytes, "filename": string object
payload = {"pdf":pdf,"filename":os.path.basename(path_to_pdf).split(".")[0]}

# post request

result =  requests.post(url=url, files=payload).json()

# the resulting json always has a field called as success, which returns True or False accordingly
if result["success"] == True:
    print(result["data"].keys())

But, When I send a request using Postman I get a 400 Error! Below is the screen shot of the error

I don't understand. How can I change my server code so that it works with Postman and also Python client programs

You shouldn't add any quotes to keys in form-data in Postman. — Fine, Mar 21 '19 at 10:44
[hope this helps](https://stackoverflow.com/questions/16015548/tool-for-sending-multipart-form-data-request) — Danila Ganchar, Mar 21 '19 at 12:41
There may be multiple causes apart from quoted keys. Please add your flask server's stacktrace which follows 400 error. — Fine, Mar 21 '19 at 13:54

score -1 · Answer 1 · answered Sep 18 '19 at 13:45

-1

I just did the same thing, and I think it's because of the double quotes you are putting in key and value, try to take them out.

answered Sep 18 '19 at 13:45

alessandro

1

It won't remain a valid JSON – Prakash Mar 08 '23 at 08:28

Unable to send POST request from postman to API made using Flask

1 Answers1