1CURLOPT_HTTPHEADER(3) curl_easy_setopt options CURLOPT_HTTPHEADER(3)
2
3
4
6 CURLOPT_HTTPHEADER - set custom HTTP headers
7
9 #include <curl/curl.h>
10
11 CURLcode curl_easy_setopt(CURL *handle, CURLOPT_HTTPHEADER, struct
12 curl_slist *headers);
13
15 Pass a pointer to a linked list of HTTP headers to pass to the server
16 and/or proxy in your HTTP request. The same list can be used for both
17 host and proxy requests!
18
19 The linked list should be a fully valid list of struct curl_slist
20 structs properly filled in. Use curl_slist_append(3) to create the list
21 and curl_slist_free_all(3) to clean up an entire list. If you add a
22 header that is otherwise generated and used by libcurl internally, your
23 added one will be used instead. If you add a header with no content as
24 in 'Accept:' (no data on the right side of the colon), the internally
25 used header will get disabled. With this option you can add new head‐
26 ers, replace internal headers and remove internal headers. To add a
27 header with no content (nothing to the right side of the colon), use
28 the form 'MyHeader;' (note the ending semicolon).
29
30 The headers included in the linked list must not be CRLF-terminated,
31 because libcurl adds CRLF after each header item. Failure to comply
32 with this will result in strange bugs because the server will most
33 likely ignore part of the headers you specified.
34
35 The first line in a request (containing the method, usually a GET or
36 POST) is not a header and cannot be replaced using this option. Only
37 the lines following the request-line are headers. Adding this method
38 line in this list of headers will only cause your request to send an
39 invalid header. Use CURLOPT_CUSTOMREQUEST(3) to change the method.
40
41 When this option is passed to curl_easy_setopt(3), libcurl will not
42 copy the entire list so you must keep it around until you no longer use
43 this handle for a transfer before you call curl_slist_free_all(3) on
44 the list.
45
46 Pass a NULL to this option to reset back to no custom headers.
47
48 The most commonly replaced headers have "shortcuts" in the options CUR‐
49 LOPT_COOKIE(3), CURLOPT_USERAGENT(3) and CURLOPT_REFERER(3). We recom‐
50 mend using those.
51
52 There's an alternative option that sets or replaces headers only for
53 requests that are sent with CONNECT to a proxy: CURLOPT_PROXYHEADER(3).
54 Use CURLOPT_HEADEROPT(3) to control the behavior.
55
57 By default, this option makes libcurl send the given headers in all
58 HTTP requests done by this handle. You should therefore use this option
59 with caution if you for example connect to the remote site using a
60 proxy and a CONNECT request, you should to consider if that proxy is
61 supposed to also get the headers. They may be private or otherwise sen‐
62 sitive to leak.
63
64 Use CURLOPT_HEADEROPT(3) to make the headers only get sent to where you
65 intend them to get sent.
66
67 Custom headers are sent in all requests done by the easy handles, which
68 implies that if you tell libcurl to follow redirects (CURLOPT_FOLLOWLO‐
69 CATION(3)), the same set of custom headers will be sent in the subse‐
70 quent request. Redirects can of course go to other hosts and thus those
71 servers will get all the contents of your custom headers too.
72
73 Starting in 7.58.0, libcurl will specifically prevent "Authorization:"
74 headers from being sent to other hosts than the first used one, unless
75 specifically permitted with the CURLOPT_UNRESTRICTED_AUTH(3) option.
76
77 Starting in 7.64.0, libcurl will specifically prevent "Cookie:" headers
78 from being sent to other hosts than the first used one, unless specifi‐
79 cally permitted with the CURLOPT_UNRESTRICTED_AUTH(3) option.
80
82 NULL
83
85 HTTP
86
88 CURL *curl = curl_easy_init();
89
90 struct curl_slist *list = NULL;
91
92 if(curl) {
93 curl_easy_setopt(curl, CURLOPT_URL, "http://example.com");
94
95 list = curl_slist_append(list, "Shoesize: 10");
96 list = curl_slist_append(list, "Accept:");
97
98 curl_easy_setopt(curl, CURLOPT_HTTPHEADER, list);
99
100 curl_easy_perform(curl);
101
102 curl_slist_free_all(list); /* free the list again */
103 }
104
105
107 As long as HTTP is enabled
108
110 Returns CURLE_OK if HTTP is supported, and CURLE_UNKNOWN_OPTION if not.
111
113 CURLOPT_CUSTOMREQUEST(3), CURLOPT_HEADEROPT(3), CURLOPT_PROXYHEADER(3),
114 CURLOPT_HEADER(3)
115
116
117
118libcurl 7.64.0 December 30, 2018 CURLOPT_HTTPHEADER(3)