Get the data received in a Flask request

Question

I want to be able to get the data sent to my Flask app  I ve tried accessing request data but it is an empty string  How do you access request data   from flask import request   app route      methods   GET    POST    def parse request        data   request data    data is empty       need posted data here     The answer to this question led me to ask Get raw POST body in Python Flask regardless of Content-Type header next  which is about getting the raw data rather than the parsed data

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If you post JSON with content type application json  use request get json   to get it in Flask  If the content type is not correct  None is returned  If the data is not JSON  an error is raised    app route   something   methods   POST    def do something        data   request get json

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Here s an example of posting form data to add a user to a database  Check request method     POST  to check if the form was submitted  Use keys from request form to get the form data  Render an HTML template with a  lt form gt  otherwise  The fields in the form should have name attributes that match the keys in request form   from flask import Flask  request  render template  app   Flask   name      app route   user add   methods   GET    POST    def add user        if request method     POST           user   User              username request form  username                email request form  email                      db session add user          db session commit           return redirect url for  index         return render template  add user html      lt form method  post  gt       lt label for  username  gt Username lt  label gt       lt input type  text  name  username  id  username  gt       lt label for  email  gt Email lt  label gt       lt input type  email  name  email  id  email  gt       lt input type  submit  gt   lt  form gt

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To parse JSON  use request get json      app route   something   methods   POST    def do something        result   handle request get json        return jsonify data result

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app route   addData   methods   POST    def add data         data in   mongo db Data      id   request values get  quot id quot        name   request values get  quot name quot        newuser     id    id   name    name       if voter find   id    id   name    name   count    gt  0              return  quot Data Exists quot       else              data in insert newuser              return  quot Data Added quot

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If the content type is recognized as form data  request data will parse that into request form and return an empty string   To get the raw data regardless of content type  call request get data    request data calls get data parse form data True   while the default is False if you call it directly

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To post JSON with jQuery in JavaScript  use JSON stringify to dump the data  and set the content type to application json   var value data    1  2  3  4      ajax       type   POST       url    process       data  JSON stringify value data       contentType   application json       success  function  response data            alert  success                   Parse it in Flask with request get json     data   request get json

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When posting form data with an HTML form  be sure the input tags have name attributes  otherwise they won t be present in request form    app route      methods   GET    POST    def index        print request form      return      lt form method  post  gt       lt input type  text  gt       lt input type  text  id  txt2  gt       lt input type  text  name  txt3  id  txt3  gt         lt input type  submit  gt   lt  form gt        ImmutableMultiDict    txt3    text 3       Only the txt3 input had a name  so it s the only key present in request form

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The docs describe the attributes available on the request   In most common cases request data will be empty because it s used as a fallback      request data Contains the incoming request data as string in case it came with a mimetype Flask does not handle     request args  the key value pairs in the URL query string request form  the key value pairs in the body  from a HTML post form  or JavaScript request that isn t JSON encoded request files  the files in the body  which Flask keeps separate from form  HTML forms must use enctype multipart form-data or files will not be uploaded  request values  combined args and form  preferring args if keys overlap request json  parsed JSON data  The request must have the application json content type  or use request get json force True  to ignore the content type    All of these are MultiDict instances  except for json   You can access values using    request form  name    use indexing if you know the key exists request form get  name    use get if the key might not exist request form getlist  name    use getlist if the key is sent multiple times and you want a list of values  get only returns the first value

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To get the raw post body regardless of the content type  use request get data    If you use request data  it calls request get data parse form data True   which will populate the request form MultiDict and leave data empty

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If the body is recognized as form data  it will be in request form  If it s JSON  it will be in request get json    Otherwise the raw data will be in request data  If you re not sure how data will be submitted  you can use an or chain to get the first one with data   def get request data        return           request args         or request form         or request get json force True  silent True          or request data         request args contains args parsed from the query string  regardless of what was in the body  so you would remove that from get request data   if both it and a body should data at  the same time

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request data  This is great to use but remember that it comes in as a string and will need iterated through

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The raw data is passed in to the Flask application from the WSGI server as request stream  The length of the stream is in the Content-Length header   length   request headers  Content-Length   data   request stream read length    It is usually safer to use request get data   instead

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To get the raw data  use request data  This only works if it couldn t be parsed as form data  otherwise it will be empty and request form will have the parsed data   from flask import request request data

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Use request get json   to get posted JSON data   data   request get json   name   data get  name         Use request form to get data when submitting a form with the POST method   name   request form get  name         Use request args to get data passed in the query string of the URL  like when submitting a form with the GET method   request args get  name         request form etc  are dict-like  use the get method to get a value with a default if it wasn t passed

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For URL query parameters  use request args   search   request args get  search   page   request args get  page     For posted form input  use request form   email   request form get  email   password   request form get  password     For JSON posted with content type application json  use request get json     data   request get json

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Here s an example of parsing posted JSON data and echoing it back   from flask import Flask  request  jsonify  app   Flask   name      app route   foo   methods   POST     def foo        data   request json     return jsonify data    To post JSON with curl   curl -i -H  Content-Type  application json  -X POST -d    userId   1    username    fizz bizz    http   localhost 5000 foo   Or to use Postman

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To get JSON posted without the application json content type  use request get json force True     app route   process data   methods   POST    def process data        req data   request get json force True      language   req data  language       return  The language value is      format language

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My problem was similar  I got a payload POST request when a user clicked a button from my slackbot  The Content-Type was application x-www-form-urlencoded  I used Flask  Python3  I tried this solution and it didn t work  app route   process data   methods   POST    def process data       req data   request get json force True     language   req data  language      return  The language value is      format language   My solution 1 was  from urllib parse import parse qs   Some code   app route   slack request handler   methods   POST    def request handler              request get data   returned a bytestring       parse qs   returned a dict from a bytestring  This dict has 1 pair       I tried payload dict keys   to see what keys in the dict and it had one key only     payload dict   parse qs request get data           Get the value of the key from payload dict       Value of the key from payload dict is an array  length   1     payload dict value arr   payload dict b payload          Get data from the index 0  of the array payload dict value arr     data   payload dict value arr 0            convert a string  representation of a Dict   to a Dict       Note that if you have single quotes as a part of your keys or values this will       fail due to improper character replacement        This solution is only recommended if you have a strong aversion        to the eval solution      datajson   json loads data         get value of key  quot channel quot      channel   datajson  quot channel quot       print channel    id    D01ACC2E8S3    name    directmessage    My solution 2  a bit shorter    app route   slack request handler   methods   POST    def request handler       payload   request form    return an ImmutableMultiDict with 1 pair     a1   payload  payload      get value of key  payload        Note that if you have single quotes as a part of your keys or values this will      fail due to improper character replacement       convert a string  representation of a Dict   to a Dict    a2   json loads a1        get value of key  quot channel quot     channel   a2  quot channel quot       print channel      id    D01ACC2E8S3    name    directmessage    flask Request get data   Unicode in Flask

User · Answer

To get request form as a normal dictionary   use request form to dict flat False     To return JSON data for an API  pass it to jsonify    This example returns form data as JSON data    app route   form to json   methods   POST    def form to json        data   request form to dict flat False      return jsonify data    Here s an example of POST form data with curl  returning as JSON     curl http   127 0 0 1 5000 data -d  name ivanleoncz amp role Software Developer       name    ivanleoncz       role    Software Developer

[python] Get the data received in a Flask request

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