Trey Mack Trey Mack - 1 year ago 96
reST (reStructuredText) Question

Sending ETag with $resource

Using Angular JS's $resource service, is there a way to specify the If-None-Match and ETag headers for the 2nd, 3rd, etc polls of a resource?

var SummarySearch = $resource(<<apiurl>>,
{ },
get: {
method: 'GET',
headers: {
'x-header': 'id'

I've gotten this to work for setting a constant header (it's just
x-header: id
in this case), but I need something that varies per request, based on the ETag I last saw.


looked promising, but I don't have access to the data that I initiated the request with, or the URL where that data ended up. As far as I can tell I only have access to the body I'd be POSTing (undefined in my case since I'm doing a GET) and the headersGetter function.

Answer Source

I discovered that $resource handles ETags on its own.

I hadn't implemented the server side of things when I posted this question. I set up If-None-Match handling server side figuring I'd have to just use the $http service on the client, but tried it out with my existing $resource .get call and it handles setting up the If-None-Match header automatically after my first poll of the resource.

I am reusing the 1 instance that $resource returned during setup.


AND I have the real-deal jQuery instead of jqLite. That's where If-None-Match seems to be set.

    // Set the If-Modified-Since and/or If-None-Match header, if in ifModified mode.
    if ( s.ifModified ) {
        ifModifiedKey = ifModifiedKey || s.url;
        if ( jQuery.lastModified[ ifModifiedKey ] ) {
            jqXHR.setRequestHeader( "If-Modified-Since", jQuery.lastModified[ ifModifiedKey ] );
        if ( jQuery.etag[ ifModifiedKey ] ) {
            jqXHR.setRequestHeader( "If-None-Match", jQuery.etag[ ifModifiedKey ] );
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