TRACE
The TRACE
HTTP method performs a message loop-back test along the path to the target resource.
The final recipient of the request should reflect the message as received (excluding any fields that might include sensitive data) back to the client as the message body of a 200 OK
response with a Content-Type
of message/http
.
The final recipient is either the origin server or the first server to receive a Max-Forwards
value of 0
in the request.
The client must not send content in the request, or generate headers that might include sensitive data such as user credentials or cookies.
Not all servers implement the TRACE
method, and some server owners have historically disallowed the use of the TRACE
method due to security concerns.
In such cases, a 405 Method Not Allowed
client error response will be sent.
Request has body | No |
---|---|
Successful response has body | Yes |
Safe | Yes |
Idempotent | Yes |
Cacheable | No |
Allowed in HTML forms | No |
Syntax
TRACE <request-target>["?"<query>] HTTP/1.1
<request-target>
-
Identifies the target resource of the request when combined with the information provided in the
Host
header. This is an absolute path (e.g.,/path/to/file.html
) in requests to an origin server, and an absolute URL in requests to proxies (e.g.,http://www.example.com/path/to/file.html
). <query>
Optional-
An optional query component preceded by a question-mark
?
. Often used to carry identifying information in the form ofkey=value
pairs.
Examples
Successful TRACE request
A TRACE
request can be performed using curl
:
curl -v -X TRACE example.com
This produces the following HTTP request:
TRACE / HTTP/1.1
Host: example.com
User-Agent: curl/8.7.1
Accept: */*
A 200 OK
response with the request headers contained in response body is sent back to the client:
HTTP/1.1 200 OK
Content-Length: 123
Date: Wed, 04 Sep 2024 11:50:24 GMT
Server: Apache/2.4.59 (Unix)
Content-Type: message/http
TRACE / HTTP/1.1
Host: example.com
User-Agent: curl/8.7.1
Accept: */*
Specifications
Specification |
---|
HTTP Semantics # TRACE |