CODEWITHSUNDEEP
javascripterror-handlingxmlhttprequest
user4244405
user4244405

Reputation:

JavaScript XHR - get raw response data on non-200 status if responseType was set as json

Is it possible to get the "raw" (text/data) from an XMLHttpRequest response if the responseType was dynamically set to json prior to sending the request?

I suppose it could be done conditionally with another request to the same URL with overrideMimeType, but that could be unwise - regarding server logs or any other processes.

Here is an example:

var xhr = new XMLHttpRequest();

xhr.open('GET','/some/path.wtf');
xhr.responseType = 'json';

xhr.onloadend = function()
{
  if (this.status !== 200)
  {
    console.log(this.response);  // null
    // send the response-text to an error handler .. sigh :(
    return;
  }
};

xhr.send();

In the actual code of my project, a request for a "/folder/path/" is regarded as a request for JSON and the server responds with JSON; unless there was an issue, or a client.console.log() routine was invoked for debugging/testing.

Any input will be appreciated, thank you.

Upvotes: 2

Views: 1916

Answers (1)

user4244405
user4244405

Reputation:

The following is a solution to the problem; however, it is a work-around -but may be helpful to others facing the same problem:

var pth,ext,rsp,xhr;

pth = '/some/path/';
rsp = ((path.substr(-1) == '/') ? 'json' : 'blob');  // for example
xhr = new XMLHttpRequest();

xhr.patchJSON = ((rsp == 'json') ? 1 : 0);
xhr.open('GET',pth);
xhr.responseType = ((rsp == 'json') ? 'text' : rsp);

xhr.onloadend = function()
{
  if (this.status !== 200)
  {
    console.log(this.response);  // response-text from server
    // send the response-text to an error handler .. yayy :)
    return;
  }

  if (this.patchJSON)
  {
    rsp = JSON.parse(this.response);

    if ((rsp === null) && (this.response.trim().length > 0))
    {
      console.log('json syntax error in: '+pth);
      // send `rsp` to the error handler
      return;
    }
  }

  // handle blobs/markup/etc, -or:
  console.log(rsp);
};

xhr.send();

Upvotes: 1

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