Uploading and Processing files with Flask Rest API - python

I want to create a REST API using Flask. I have two files at any given time, I will call my API and send these two files, a python script will run on the API side and send me back a JSON Response. Now this is the overall idea of my application , but I don't know how to do all this. As I do not want to save those two files, just take them as an Input and send the result back, I don't think i will need to save the files. But I do not know how to send files to the API, logic part is ready, I just need to know how to send two files, process them and send back the response in just one API call. Thanks in advance
I have just setup the basic API till now.
from flask import Flask
app = Flask(__name__)
#app.route('/')
def index():
return 'Server works'
if __name__== '__main__':
app.run(debug=True)

Found this on the Flask documentation:
import os
from flask import Flask, flash, request, redirect, url_for
from werkzeug.utils import secure_filename
UPLOAD_FOLDER = '/path/to/the/uploads'
ALLOWED_EXTENSIONS = {'txt', 'pdf', 'png', 'jpg', 'jpeg', 'gif'}
app = Flask(__name__)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
def allowed_file(filename):
return '.' in filename and \
filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS
#app.route('/', methods=['GET', 'POST'])
def upload_file():
if request.method == 'POST':
# check if the post request has the file part
if 'file' not in request.files:
flash('No file part')
return redirect(request.url)
file = request.files['file']
# if user does not select file, browser also
# submit an empty part without filename
if file.filename == '':
flash('No selected file')
return redirect(request.url)
if file and allowed_file(file.filename):
filename = secure_filename(file.filename)
file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
return redirect(url_for('uploaded_file',
filename=filename))
return '''
<!doctype html>
<title>Upload new File</title>
<h1>Upload new File</h1>
<form method=post enctype=multipart/form-data>
<input type=file name=file>
<input type=submit value=Upload>
</form>
'''
In your API backend, you will receive the file by using file = request.files['file']. The name "file" comes from the name of the input tag in the HTML Form you are using to send the file to your backend.
'''
<!doctype html>
<title>Upload new File</title>
<h1>Upload new File</h1>
<form method=post enctype=multipart/form-data>
<input type=file name=file>
<input type=submit value=Upload>
</form>
'''
In this example, the backend is saving the uploaded files to UPLOAD_FOLDER. This example is also using some exception handling to make sure that the user is uploading the correct type of file types.
[EDIT] I misread your question. If you just want to send back a JSON response instead of JSON containing the files content you would do this:
return jsonify({"response": "success"})
Finally, here's a link to the full Flask documentation

Related

how to use Flask to save both uploaded file and user text input in json

in html, I have
<form method="POST" enctype="multipart/form-data" action="/">
<input type="number" name="speed " id="speed">
<input type="file" id="stl_file">
<input type="submit" value="submit">
</form>
I would like to save the value for speed in json file and save the uploaded stl file as well.
What I did in my app.py is
from flask import Flask, render_template, request,flash, redirect, url_for
from werkzeug.utils import secure_filename
import os
import json
app = Flask(__name__)
ALLOWED_EXTENSIONS = {'stl','STL'}
def allowed_file(filename):
return '.' in filename and \
filename.rsplit('.', 1)[1].lower() in ALLOWED_EXTENSIONS
#app.route("/")
def index():
return render_template('main.html')
#app.route('/' , methods=['POST'])
def get_data():
if request.method == 'POST':
results =request.form
file = request.files['stl_file']
with open('file.json','w') as f:
json.dump(results, f)
if 'file' not in request.files:
flash('No file part')
return redirect(request.url)
# if user does not select file, browser also
# submit an empty part without filename
if file.filename == '':
flash('No selected file')
return redirect(request.url)
if file and allowed_file(file.filename):
filename = secure_filename(file.filename)
file.save(filename)
return redirect(url_for('index'))
return render_template('main.html')
if __name__ == '__main__':
app.run()
I can run it and I see my main page. However, when I input a number into speed, upload a file, and click submit, I get
Bad Request
The browser (or proxy) sent a request that this server could not understand.
Any suggestion on that? Thanks in advance.
You haven't defined the name attribute of file.
<input type="file" name="stl_file" id="stl_file">

In Flask, how do I store a user submitted file temporarily to manipulate it and return it back?

So I've been working on a Flask application where the user submits a file to a form, the server takes it and manipulates it, then returns the edited file back to the user. I am new to Flask and web dev in general, so bear with me. I have already set up the website with the form and a filefield, but Im not exactly sure how I can get the data from the file. Do i have to store it on the server? If I do, do I have to delete after im done?
Here is what I've got so far in my routes
#app.route('/mysite', methods=['post', 'get'])
def mysite():
form = mysiteform()
if request.method == 'POST' and form.validate():
file = form.file.data.read()
filename = secure_filename(file.filename)
return render_template('mysite.html', title = 'hello world!', form=form)
In Flask official documentation site, there is a file uploader example as below:
#app.route('/', methods=['GET', 'POST'])
def upload_file():
if request.method == 'POST':
# check if the post request has the file part
if 'file' not in request.files:
flash('No file part')
return redirect(request.url)
file = request.files['file']
# If the user does not select a file, the browser submits an
# empty file without a filename.
if file.filename == '':
flash('No selected file')
return redirect(request.url)
if file and allowed_file(file.filename):
filename = secure_filename(file.filename)
file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
return redirect(url_for('download_file', name=filename))
return '''
<!doctype html>
<title>Upload new File</title>
<h1>Upload new File</h1>
<form method=post enctype=multipart/form-data>
<input type=file name=file>
<input type=submit value=Upload>
</form>
'''
Here is how you can get the file content: file = request.files['file'] and of course you can do further manipulation on the file.
Here is how you can save the file file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename)). It's really up to you if you want to save the file and return the file later or just modify it in memory and return it immediately.

Can't get other files uploaded [python flask] with html

The problem is i am able to upload file which are in the same directory as main.py but I am unable to upload other files which are not in the same folder of main.py, suppose - main.py is in c:\users\prabhat\upload\ and the file i am uploading the file is also in c:\users\prabhat\upload\ directory, but if there is file in c:\desktop\B.xlsx then if i upload, then it shows Error, file not found.
how an i resolve this??
index.html code
<form class="" action="data" method="post">
<input type="file" name="upload-file" value="">
<input type="submit" name="" value="Submit">
</form>
main.py
from flask import Flask, render_template, request
import pandas as pd
app = Flask(__name__)
#app.route('/', methods=['GET', 'POST'])
def index():
return render_template('index.html')
#app.route('/data', methods=['GET', 'POST'])
def data():
if request.method == 'POST':
file = request.form['upload-file']
return '''
successfully Done!
'''
if __name__ == '__main__':
app.run(debug=True)
You don't access files uploaded through flask via request.form but rather through request.files. This should get you a valid file handle:
if request.method == 'POST':
file = request.files['upload-file']
See https://flask.palletsprojects.com/en/2.2.x/patterns/fileuploads/ for more info.
Try file = request.files['upload-file'] instead of request.form, and I guess you want to save it to the server, do it with file.save("path/to/your/folder/filename.extension")

How do I send an image taken in react to a flask api and run python script?

I am trying to put together a flask api endpoint that can take an image, drop it in a an 'uploads' folder and then perform an operation on it. The image will be sent from a reactjs front end. I have the beginnings of a python script that I know allows me to upload a photo via flask. But I want to alter it to:
lose the front end upload option instead giving me just the endpoint to upload the image
set it up to run a python script on that image once it lands in the uploads folder that extracts text
I've put below some of the pieces I have so far:
reactjs
#just the piece where i am sending an image to flask
fileUploadHandler =() => {
const fd = new FormData();
fd.append('image', this.state.selectedFile, this.state.selectedFile.name)
console.log('file is uploaded')
//axios.post('my_endpoint');
}
app.py
#from https://stackoverflow.com/questions/52152464/convert-normal-python-script-to-reset-api
import sumTwoNumbers
from flask import Flask, request
from flask_restful import Resource, Api
import os
from werkzeug.utils import secure_filename
import cv2
PROJECT_HOME = os.path.dirname(os.path.realpath(__file__))
UPLOAD_FOLDER = '{}/uploads/'.format(PROJECT_HOME)
app = Flask(__name__)
api = Api(app)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
ALLOWED_EXTENSIONS = set(['jpg','png'])
def allowed_file(filename):
return '.' in filename and \
filename.rsplit('.', 1)[1] in ALLOWED_EXTENSIONS
#app.route("/", methods=['GET', 'POST'])
def index():
if request.method == 'POST':
file = request.files['file']
if file and allowed_file(file.filename):
filename = secure_filename(file.filename)
file.save(os.path.join(app.config['UPLOAD_FOLDER'], filename))
_path = os.path.abspath("<FILE PATH>")
#uf = str(uuid.uuid4())
return redirect(url_for('index'))
return """
<!doctype html>
<title>Upload new File</title>
<h1>Upload new File</h1>
<form action="" method=post enctype=multipart/form-data>
<p><input type=file name=file>
<input type=submit value=Upload>
</form>
<p>%s</p>
""" % "<br>".join(os.listdir(app.config['UPLOAD_FOLDER'],))
if __name__ == "__main__":
app.run(host='0.0.0.0', port=5000, debug=True)
imageToText.py
#script to run on the image that pulls text
import cv2
import pytesseract
import imutils
img = cv2.imread('note.PNG')
#use tesseract to convert image into strinf
text = pytesseract.image_to_string(img, lang='eng')
print(text)

upload image flask error

I'm following the Flask tutorial for image uploading. I also decided to tinker with it a bit so that I can add other features. The website loads locally, but when I actually click on the upload button (after selecting a .png image), I get the following error:
Bad Request. The browser (or proxy) sent a request that this server could not understand.
I've read something about adding an else statement here:
Form sending error, Flask
But I'm not sure how to accommodate it for my needs.
Here is my code:
from flask import Flask, request, session, g, redirect, url_for, \
abort, render_template, flash
from werkzeug import secure_filename
import os
DEBUG = True
SECRET_KEY = 'development key'
USERNAME = 'admin'
PASSWORD = 'default'
#Add parameters for image uploads:
UPLOAD_FOLDER = '/upload_folder/'
ALLOWED_EXTENSIONS = set(['png','jpg','jpeg'])
app = Flask(__name__)
app.config['UPLOAD_FOLDER'] = UPLOAD_FOLDER
##app.route('/')
##app.route('/<name>')
#Image uploads:
def allowed_file(filename):
return '.' in filename and \
filename.rsplit('.',1)[1] in ALLOWED_EXTENSIONS
#app.route('/',methods=['GET','POST'])
def upload_file():
if request.method == 'POST':
file = request.files['file']
if file and allowed_file(file.filename):
filename = secure_filename(file.filename)
file.save(os.path.join(app.config['UPLOAD_FOLDER'],filename))
return redirect(url_for('uploaded_file',filename=filename))
return '''
<!doctype html>
<title>Upload new File</title>
<h1>UPload new File</h1>
<form action="" method=post enctype=multpart/form-data>
<p><input type=file name=file>
<input type=submit value=Upload>
</form>
'''
#Handle errors:
#app.errorhandler(404)
def page_not_found(error):
return render_template('page_not_found.html'),404
#render template:
def flaskr(name=None):
return render_template('hello.html',name=name)
#Handle errors:
#app.errorhandler(404)
def page_not_found(error):
return render_template('page_not_found.html'),404
if __name__ == '__main__':
app.run()
There is a typo in your html code:
<form action="" method=post enctype=multpart/form-data>
should be multipart and not multpart.

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