How to Call Curl Without Using Server-Side Cache

How to call cURL without using server-side cache?

I know this is an older question, but I wanted to post an answer for users with the same question:

curl -H 'Cache-Control: no-cache' http://www.example.com

This curl command servers in its header request to return non-cached data from the web server.

Is there a way to tell curl to not use cache

You can use CURLOPT_FRESH_CONNECT for this. From curl_setopt

CURLOPT_FRESH_CONNECT TRUE to force the use of a new connection instead of a cached one.

curl_setopt($curl1, CURLOPT_FRESH_CONNECT, TRUE);

According to RFC 7234 - Hypertext Transfer Protocol (HTTP/1.1): Caching and 5.2. Cache-Control

The "Cache-Control" header field is used to specify directives for
caches along the request/response chain.

5.2.1. Request Cache-Control Directives defines several directives to control the use of caches for a response. One of these is

5.2.1.4. no-cache

The "no-cache" request directive indicates that a cache MUST NOT use
a stored response to satisfy the request without successful
validation on the origin server.

So setting an appropriate header with

curl_setopt($curl1, CURLOPT_HTTPHEADER, array("Cache-Control: no-cache"));

should ensure, that a valid and up to date response will be returned. I understand, that this may still result in a cached response, if the validation on the server allows to do so.

However, 5.2.2.1. must-revalidate is a Response Cache-Control Directive given by a server together with the response to a request

[...]
The must-revalidate directive ought to be used by servers if and only
if failure to validate a request on the representation could result
in incorrect operation, such as a silently unexecuted financial
transaction.

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