103 lines
3.2 KiB
Markdown
103 lines
3.2 KiB
Markdown
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---
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c: Copyright (C) Daniel Stenberg, <daniel@haxx.se>, et al.
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SPDX-License-Identifier: curl
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Title: CURLOPT_FOLLOWLOCATION
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Section: 3
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Source: libcurl
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See-also:
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- CURLINFO_REDIRECT_COUNT (3)
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- CURLINFO_REDIRECT_URL (3)
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- CURLOPT_POSTREDIR (3)
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- CURLOPT_PROTOCOLS_STR (3)
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- CURLOPT_REDIR_PROTOCOLS_STR (3)
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- CURLOPT_UNRESTRICTED_AUTH (3)
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Protocol:
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- HTTP
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Added-in: 7.1
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---
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# NAME
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CURLOPT_FOLLOWLOCATION - follow HTTP 3xx redirects
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# SYNOPSIS
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~~~c
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#include <curl/curl.h>
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CURLcode curl_easy_setopt(CURL *handle, CURLOPT_FOLLOWLOCATION, long enable);
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~~~
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# DESCRIPTION
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A long parameter set to 1 tells the library to follow any Location: header
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redirects that an HTTP server sends in a 30x response. The Location: header
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can specify a relative or an absolute URL to follow.
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libcurl issues another request for the new URL and follows subsequent new
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`Location:` redirects all the way until no more such headers are returned or
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the maximum limit is reached. CURLOPT_MAXREDIRS(3) is used to limit the number
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of redirects libcurl follows.
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libcurl restricts what protocols it automatically follow redirects to. The
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accepted target protocols are set with CURLOPT_REDIR_PROTOCOLS_STR(3). By
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default libcurl allows HTTP, HTTPS, FTP and FTPS on redirects.
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When following a redirect, the specific 30x response code also dictates which
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request method libcurl uses in the subsequent request: For 301, 302 and 303
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responses libcurl switches method from POST to GET unless CURLOPT_POSTREDIR(3)
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instructs libcurl otherwise. All other redirect response codes make libcurl
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use the same method again.
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For users who think the existing location following is too naive, too simple
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or just lacks features, it is easy to instead implement your own redirect
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follow logic with the use of curl_easy_getinfo(3)'s CURLINFO_REDIRECT_URL(3)
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option instead of using CURLOPT_FOLLOWLOCATION(3).
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By default, libcurl only sends `Authentication:` or explicitly set `Cookie:`
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headers to the initial host given in the original URL, to avoid leaking
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username + password to other sites. CURLOPT_UNRESTRICTED_AUTH(3) is provided
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to change that behavior.
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Due to the way HTTP works, almost any header can be made to contain data a
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client may not want to pass on to other servers than the initially intended
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host and for all other headers than the two mentioned above, there is no
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protection from this happening when libcurl is told to follow redirects.
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# NOTE
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Since libcurl changes method or not based on the specific HTTP response code,
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setting CURLOPT_CUSTOMREQUEST(3) while following redirects may change what
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libcurl would otherwise do and if not that carefully may even make it
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misbehave since CURLOPT_CUSTOMREQUEST(3) overrides the method libcurl would
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otherwise select internally.
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# DEFAULT
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0, disabled
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# %PROTOCOLS%
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# EXAMPLE
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~~~c
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int main(void)
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{
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CURL *curl = curl_easy_init();
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if(curl) {
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curl_easy_setopt(curl, CURLOPT_URL, "https://example.com");
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/* example.com is redirected, so we tell libcurl to follow redirection */
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curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
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curl_easy_perform(curl);
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}
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}
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~~~
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# %AVAILABILITY%
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# RETURN VALUE
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Returns CURLE_OK if HTTP is supported, and CURLE_UNKNOWN_OPTION if not.
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