CODEWITHSUNDEEP
javascriptjqueryajaxpromisebluebird
BentOnCoding
BentOnCoding

Reputation: 28168

How do you access http headers when making ajax requests with Promises?

I am resolve jquery ajax requests using bluebird.js, and it is surprisingly difficult to access the http headers of my request.

Sample Code : 

Promise.resolve($.get(...)).then(function(data){    
    //wtb http headers
});

I am trying to get access to the http headers returned with my response. Doing this on just an ajax request is simple, I assume someone smarter than me has figured this out already for promises.

Upvotes: 0

Views: 950

Answers (3)

Roamer-1888
Roamer-1888

Reputation: 19288

Why coerce the jqXHR to some other Promise when, by staying in jQuery, the jqXHR is made available to both success and error handlers as a formal variable?

$.get(...).then(function(data, testStatus, jqXHR) {
    var headers = jqXHR.getAllResponseHeaders();
    ...
}, function(jqXHR, testStatus, errorThrown) {
    var headers = jqXHR.getAllResponseHeaders();
    ...
});

If for whatever reason you still need to coerce the jqXHR, then wrap the whole expression in Promise.resolve(...). The jQuery promise returned by .then() is every bit as coercible as a jqXHR.

Upvotes: 1

Paul
Paul

Reputation: 141827

One way to solve this, is just to keep a reference to the jqXHR object around, so you can access it later:

var jqXHR = $.get(...);

Promise.resolve( jqXHR ).then( function ( data ) { 
    var headers = jqXHR.getAllResponseHeaders();
} );

Upvotes: 4

gilly3
gilly3

Reputation: 91497

One difference between jQuery promises and bluebird promises (which are Promises/A+ compliant), is that your then function gets only one parameter. If you want to retain all the information that jQuery gives you, you have to wrap it up in a single object:

Promise.resolve($.get(...).then(function(data, status, xhr) {
    return {
        data: data,
        status: status,
        xhr: xhr
    };
})).then(function (data) {
    // data.data has the response data
    // data.xhr contains the jqXHR object
});

Upvotes: 2

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