Content-Location
The Content-Location
header indicates an alternate
location for the returned data. The principal use is to indicate the URL of a resource
transmitted as the result of content negotiation.
Location
and Content-Location
are different.
Location
indicates the URL of a redirect, while
Content-Location
indicates the direct URL to use to access the resource,
without further content negotiation in the future. Location
is a header
associated with the response, while Content-Location
is associated with the
data returned. This distinction may seem abstract without examples.
Header type | Representation header |
---|---|
Forbidden header name | no |
Syntax
http
Content-Location: <url>
Directives
Examples
Requesting data from a server in different formats
Let's say a site's API can return data in JSON, XML, or
CSV formats. If the URL for a particular document
is at https://example.com/documents/foo
, the site could return different
URLs for Content-Location
depending on the request's
Accept
header:
Request header | Response header |
---|---|
Accept: application/json, text/json |
Content-Location: /documents/foo.json |
Accept: application/xml, text/xml |
Content-Location: /documents/foo.xml |
Accept: text/plain, text/* |
Content-Location: /documents/foo.txt |
These URLs are examples — the site could serve the different filetypes with any URL
patterns it wishes, such as a query string parameter: /documents/foo?format=json
,
/documents/foo?format=xml
, and so on.
Then the client could remember that the JSON version is available at that particular URL, skipping content negotiation the next time it requests that document.
The server could also consider other content negotiation headers, such
as Accept-Language
.
Pointing to a new document (HTTP 201 Created)
Say you're creating a new blog post through a site's API:
http
POST /new/post
Host: example.com
Content-Type: text/markdown
# My first blog post!
I made this through `example.com`'s API. I hope it worked.
The site returns the published post in the response body. The server specifies where the new post is with the Content-Location
header, indicating that this location refers to the content (the body) of this response:
http
HTTP/1.1 201 Created
Content-Type: text/markdown
Content-Location: /my-first-blog-post
# My first blog post
I made this through `example.com`'s API. I hope it worked.
Indicating the URL of a transaction's result
Say you have a
<form>
for sending
money to another user of a site.
html
<form action="/send-payment" method="post">
<p>
<label
>Who do you want to send the money to?
<input type="text" name="recipient" />
</label>
</p>
<p>
<label
>How much?
<input type="number" name="amount" />
</label>
</p>
<button type="submit">Send Money</button>
</form>
When the form is submitted, the site generates a receipt for the transaction. The
server could use Content-Location
to indicate that receipt's URL for future
access.
HTTP/1.1 200 OK Content-Type: text/html; charset=utf-8 Content-Location: /my-receipts/38 <!doctype html> (Lots of HTML…) <p>You sent $38.00 to ExampleUser.</p> (Lots more HTML…)
Specifications
Specification |
---|
HTTP Semantics # field.content-location |
Browser compatibility
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