Proper way to set response status and JSON content in a REST API made with nodejs and express

Question

I am playing around with Nodejs and express by building a small rest API  My question is  what is the good practice best way to set the code status  as well as the response data   Let me explain with a little bit of code  I will not put the node and express code necessary to start the server  just the router methods that are concerned    router get   users  id   function req  res  next      var user   users getUserById req params id     res json user         exports getUserById   function id      for  var i   0  i  lt  users length  i          if  users i  id    id  return users i            The code below works perfectly  and when sending a request with Postman  I get the following result    As you can see  the status shows 200  which is OK  But is this the best way to do this  Is there a case where I should have to set the status myself  as well as the returned JSON  Or is that always handled by express   For example  I just made a quick test and slightly modified the get method above   router get   users  id   function req  res  next      var user   users getUserById req params id     if  user    null    user     undefined         res status 404         res json user         As you can see  if the user is not found in the array  I will just set a status of 404   Resources advices to learn more about this topic are more than welcome

User · Answer

try     var data    foo   bar      res json JSON stringify data      catch  e      res status 500  json JSON stringify e

User · Answer

You could do this              return res status 201  json                   statusCode  req statusCode                  method  req method                  message   Question has been added

User · Answer

The standard way to get full HttpResponse that includes following properties   body   contains your data headers ok status statusText type url   On backend  do this  router post   signup    req  res  next    gt           res object have its own statusMessage property so utilize this     res statusText    Your have signed-up succesfully      return res status 200  send  You are doing a great job        On Frontend e g  in Angular  just do    let url    http   example com signup  this http post url    profile  data          observe   response     remember to add this  you ll get pure HttpResponse    subscribe response   gt        console log response

User · Answer

res sendStatus status  has been added as of version 4 9 0 you can use one of these res sendStatus      res status   methods below is difference in between res sendStatus      res status    res sendStatus 200     equivalent to res status 200  send  OK   res sendStatus 403     equivalent to res status 403  send  Forbidden   res sendStatus 404     equivalent to res status 404  send  Not Found   res sendStatus 500     equivalent to res status 500  send  Internal Server Error     I hope someone finds this helpful thanks

User · Answer

res status 500  jsonp dataRes

User · Answer

I am using this in my Express js application   app get      function  req  res        res status 200  json           message   Welcome to the project-name api

User · Answer

FOR IIS If you are using iisnode to run nodejs through IIS  keep in mind that IIS by default replaces any error message you send  This means that if you send res status 401  json  message   quot Incorrect authorization token quot    You would get back You do not have permission to view this directory or page  This behavior can be turned off by using adding the following code to your web config file under  lt system webServer gt   source    lt httpErrors existingResponse  quot PassThrough quot    gt

User · Answer

A list of HTTP Status Codes  The good-practice regarding status response is to  predictably  send the proper HTTP status code depending on the error  4xx for client errors  5xx for server errors   regarding the actual JSON response there s no  bible  but a good idea could be to send  again  the status and data as 2 different properties of the root object in a successful response  this way you are giving the client the chance to capture the status from the HTTP headers and the payload itself  and a 3rd property explaining the error in a human-understandable way in the case of an error   Stripe s API behaves similarly in the real world   i e   OK  200   status  200  data           Error  400   status  400  data  null  message   You must send foo and bar to baz

User · Answer

You could do it this way   res status 400  json json response     This will set the HTTP status code to 400  it works even in express 4

User · Answer

status of 200 will be the default when using res send  res json  etc   You can set the status like res status 500  json   error   something is wrong       Often I ll do something like     router get   something   function req  res  next         Some stuff here   if err        res status 500       return next err            More stuff here       Then have my error middleware send the response  and do anything else I need to do when there is an error   Additionally  res sendStatus status  has been added as of version 4 9 0 http   expressjs com 4x api html res sendStatus

User · Answer

Express API reference covers this case   See status and send   In short  you just have to call the status method before calling json or send   res status 500  send   error   boo

User · Answer

The best way of sending an error response would be return res status 400  send   message   An error has occurred       Then  in your frontend you can catch it using something like this           url  your url          method   POST           headers  headers          data  JSON stringify body                   then  res    gt                console log  success   res                       catch  err    gt                err response  amp  amp  err response data  amp  amp  this setState   apiResponse  err response data                 Just logging err won t work  as your sent message object resides in err response data   Hope that helps

User · Answer

I don t see anyone mentioned the fact that the order of method calls on res object is important  I m new to nodejs and didn t realize at first that res json   does more than just setting the body of the response  It actually tries to infer the response status as well  So  if done like so  res json   quot message quot    quot Bad parameters quot    res status 400   The second line would be of no use  because based on the correctly built json express nodejs will already infer the success status 200

[node.js] Proper way to set response status and JSON content in a REST API made with nodejs and express

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