How do I consume the JSON POST data in an Express application

Question

I m sending the following JSON string to my server                       id   1          name   foo                           id   2          name   bar            On the server I have this   app post      function request  response         console log  Got response      response statusCode        response on  data   function chunk            queryResponse  chunk          console log  data                 response on  end   function            console log  end                  When I send the string  it shows that I got a 200 response  but those other two methods never run  Why is that

User · Answer

Sometimes you don t need third party libraries to parse JSON from text  Sometimes all you need it the following JS command  try it first           const res data   JSON parse body

User · Answer

For those getting an empty object in req body  I had forgotten to set  headers    Content-Type    application json   in the request  Changing it solved the problem

User · Answer

I think you re conflating the use of the response object with that of the request  The response object is for sending the HTTP response back to the calling client  whereas you are wanting to access the body of the request  See this answer which provides some guidance  If you are using valid JSON and are POSTing it with Content-Type  application json  then you can use the bodyParser middleware to parse the request body and place the result in request body of your route  For earlier versions of Express   lt  4  var express   require  express       app   express createServer     app use express bodyParser      app post      function request  response     console log request body           your JSON   response send request body         echo the result back      app listen 3000    Test along the lines of    curl -d    quot MyKey quot   quot My Value quot    -H  quot Content-Type  application json quot  http   127 0 0 1 3000    quot MyKey quot   quot My Value quot    Updated for Express 4  Body parser was split out into it s own npm package after v4  requires a separate install npm install body-parser var express   require  express       bodyParser   require  body-parser     var app   express     app use bodyParser json      app post      function request  response     console log request body           your JSON    response send request body         echo the result back      app listen 3000    Update for Express 4 16  Starting with release 4 16 0  a new express json   middleware is available  var express   require  express     var app   express     app use express json      app post      function request  response     console log request body           your JSON    response send request body         echo the result back      app listen 3000

User · Answer

Daniel Thompson mentions that he had forgotten to add   Content-Type    application json   in the request  He was able to change the request  however  changing requests is not always possible  we are working on the server here     In my case I needed to force content-type  text plain to be parsed as json   If you cannot change the content-type of the request  try using the following code   app use express json  type              Instead of using express json   globally  I prefer to apply it only where needed  for instance in a POST request   app post   mypost   express json  type            req  res    gt         echo json   res json req body

User · Answer

A beginner s mistake   i was using app use express json     in a local module instead of the main file  entry point

User · Answer

x000D   x000D  const express   require  express    x000D  let app   express    x000D  app use express json     x000D   x000D   x000D    This app use express json  will now let you read the incoming post JSON object

User · Answer

For Express v4   install body-parser from the npm     npm install body-parser   https   www npmjs org package body-parser installation  var express      require  express   var bodyParser   require  body-parser    var app   express       parse application json app use bodyParser json     app use function  req  res  next      console log req body     populated    next

[json] How do I consume the JSON POST data in an Express application

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