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23 .TH CURLOPT_HTTPHEADER 3 "January 23, 2018" "libcurl 7.59.0" "curl_easy_setopt options"
26 CURLOPT_HTTPHEADER \- set custom HTTP headers
28 #include <curl/curl.h>
30 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTPHEADER, struct curl_slist *headers);
32 Pass a pointer to a linked list of HTTP headers to pass to the server and/or
33 proxy in your HTTP request. The same list can be used for both host and proxy
36 The linked list should be a fully valid list of \fBstruct curl_slist\fP
37 structs properly filled in. Use \fIcurl_slist_append(3)\fP to create the list
38 and \fIcurl_slist_free_all(3)\fP to clean up an entire list. If you add a
39 header that is otherwise generated and used by libcurl internally, your added
40 one will be used instead. If you add a header with no content as in 'Accept:'
41 (no data on the right side of the colon), the internally used header will get
42 disabled. With this option you can add new headers, replace internal headers
43 and remove internal headers. To add a header with no content (nothing to the
44 right side of the colon), use the form 'MyHeader;' (note the ending
47 The headers included in the linked list \fBmust not\fP be CRLF-terminated,
48 because libcurl adds CRLF after each header item. Failure to comply with this
49 will result in strange bugs because the server will most likely ignore part of
50 the headers you specified.
52 The first line in a request (containing the method, usually a GET or POST) is
53 not a header and cannot be replaced using this option. Only the lines
54 following the request-line are headers. Adding this method line in this list
55 of headers will only cause your request to send an invalid header. Use
56 \fICURLOPT_CUSTOMREQUEST(3)\fP to change the method.
58 When this option is passed to \fIcurl_easy_setopt(3)\fP, libcurl will not copy
59 the entire list so you \fBmust\fP keep it around until you no longer use this
60 \fIhandle\fP for a transfer before you call \fIcurl_slist_free_all(3)\fP on
63 Pass a NULL to this option to reset back to no custom headers.
65 The most commonly replaced headers have "shortcuts" in the options
66 \fICURLOPT_COOKIE(3)\fP, \fICURLOPT_USERAGENT(3)\fP and
67 \fICURLOPT_REFERER(3)\fP. We recommend using those.
69 There's an alternative option that sets or replaces headers only for requests
70 that are sent with CONNECT to a proxy: \fICURLOPT_PROXYHEADER(3)\fP. Use
71 \fICURLOPT_HEADEROPT(3)\fP to control the behavior.
73 By default, this option makes libcurl send the given headers in all HTTP
74 requests done by this handle. You should therefore use this option with
75 caution if you for example connect to the remote site using a proxy and a
76 CONNECT request, you should to consider if that proxy is supposed to also get
77 the headers. They may be private or otherwise sensitive to leak.
79 Use \fICURLOPT_HEADEROPT(3)\fP to make the headers only get sent to where you
80 intend them to get sent.
82 Custom headers are sent in all requests done by the easy handles, which
83 implies that if you tell libcurl to follow redirects
84 (\fICURLOPT_FOLLOWLOCATION(3)\fP), the same set of custom headers will be sent
85 in the subsequent request. Redirects can of course go to other hosts and thus
86 those servers will get all the contents of your custom headers too.
88 Starting in 7.58.0, libcurl will specifically prevent "Authorization:" headers
89 from being sent to other hosts than the first used one, unless specifically
90 permitted with the \fICURLOPT_UNRESTRICTED_AUTH(3)\fP option.
97 CURL *curl = curl_easy_init();
99 struct curl_slist *list = NULL;
102 curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
104 list = curl_slist_append(list, "Shoesize: 10");
105 list = curl_slist_append(list, "Accept:");
107 curl_easy_setopt(curl, CURLOPT_HTTPHEADER, list);
109 curl_easy_perform(curl);
111 curl_slist_free_all(list); /* free the list again */
116 As long as HTTP is enabled
118 Returns CURLE_OK if HTTP is supported, and CURLE_UNKNOWN_OPTION if not.
120 .BR CURLOPT_CUSTOMREQUEST "(3), " CURLOPT_HEADEROPT "(3), "
121 .BR CURLOPT_PROXYHEADER "(3), " CURLOPT_HEADER "(3)"