[PATCH v2] Added Curl Option to Override Request Method v2

From: Drew Green via GitGitGadget <gitgitgadget@gmail.com>
Date: Apr 26, 2022, 15:57 UTC
Message-ID: <pull.1225.v2.git.1650988659280.gitgitgadget@gmail.com>
In-Reply-To: <pull.1225.git.1650970894143.gitgitgadget@gmail.com>

From: agreenbhm <agreenbhm@gmail.com>

Added support for environment variable "CURLOPT_CUSTOMREQUEST" and config option "http.customrequest" to allow setting the Curl option to override the default request method used by HTTP Git operations. Primary reason for this is to allow support for cloning repositories where only GET requests are allowed by a local web proxy but not POSTs. When cloning a repo first a GET is made to the server and then a POST is made to the "git-upload-pack" endpoint. In some corporate environments with strong controls only GET requests are allowed to known repository hosts (such as GitHub) through a web proxy to prevent data leakage. Using this new setting, a user can set the "CURLOPT_CUSTOMREQUEST=GET" env at runtime or "http.customrequest = GET" in their config file which will change the second request from a POST to a GET, bypassing web proxy restrictions on the type of requests allowed. Tested with GitHub, changing the request from POST to GET still results in the expected behavior of the repo successfully being cloned.

This is v2 of this patch, which refactored the placement of the env and added the ability to set the config file option.

Signed-off-by: agreenbhm <agreenbhm@gmail.com>
---
    Added Curl Option to Override Request Method
    
    Added support for environment variable "CURLOPT_CUSTOMREQUEST" to allow
    setting the curl option to override the default request method used by
    HTTP Git operations. Primary reason for this is to allow support for
    cloning repositories where only GET requests are allowed but not POSTs.
    When cloning a repo first a GET is made to the server and then a POST is
    made to the "git-upload-pack" endpoint. In some corporate environments
    with strong controls only GET requests are allowed to known repository
    hosts (such as GitHub) to prevent data leakage by sending data. Using
    this new environmental variable, a user can set
    "CURLOPT_CUSTOMREQUEST=GET" which will change the second request from a
    POST to a GET, bypassing web proxy restrictions on the type of requests
    allowed. Tested with GitHub, changing the request from POST to GET still
    results in the expected behavior of the repo successfully being cloned.
    
    Signed-off-by: agreenbhm agreenbhm@gmail.com

Published-As: https://github.com/gitgitgadget/git/releases/tag/pr-1225%2Fagreenbhm%2Fmaster-v2
Fetch-It-Via: git fetch https://github.com/gitgitgadget/git pr-1225/agreenbhm/master-v2
Pull-Request: https://github.com/gitgitgadget/git/pull/1225

Range-diff vs v1:

 1:  8bf14c61c2a < -:  ----------- Added Curl Option to Override Request Method
 -:  ----------- > 1:  8734bf28344 Added Curl Option to Override Request Method v2

 http.c | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/http.c b/http.c
index 229da4d1488..eaf269fc5a7 100644
--- a/http.c
+++ b/http.c
@@ -75,6 +75,7 @@ static const char *http_proxy_ssl_key;
 static const char *http_proxy_ssl_ca_info;
 static struct credential proxy_cert_auth = CREDENTIAL_INIT;
 static int proxy_ssl_cert_password_required;
+static const char *http_custom_request;
 
 static struct {
 	const char *name;
@@ -403,6 +404,9 @@ static int http_options(const char *var, const char *value, void *cb)
 		return 0;
 	}
 
+	if(!strcmp("http.customrequest", var))
+		return git_config_string(&http_custom_request, var, value);
+
 	/* Fall back on the default ones */
 	return git_default_config(var, value, cb);
 }
@@ -1099,6 +1103,7 @@ void http_init(struct remote *remote, const char *url, int proactive_auth)
 		    starts_with(url, "https://"))
 			ssl_cert_password_required = 1;
 	}
+	set_from_env(&http_custom_request, "CURLOPT_CUSTOMREQUEST");
 
 	curl_default = get_curl_handle();
 }
@@ -1212,7 +1217,7 @@ struct active_request_slot *get_active_slot(void)
 		curl_easy_setopt(slot->curl, CURLOPT_COOKIEJAR, curl_cookie_file);
 	curl_easy_setopt(slot->curl, CURLOPT_HTTPHEADER, pragma_header);
 	curl_easy_setopt(slot->curl, CURLOPT_ERRORBUFFER, curl_errorstr);
-	curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, NULL);
+	curl_easy_setopt(slot->curl, CURLOPT_CUSTOMREQUEST, http_custom_request);
 	curl_easy_setopt(slot->curl, CURLOPT_READFUNCTION, NULL);
 	curl_easy_setopt(slot->curl, CURLOPT_WRITEFUNCTION, NULL);
 	curl_easy_setopt(slot->curl, CURLOPT_POSTFIELDS, NULL);

base-commit: 6cd33dceed60949e2dbc32e3f0f5e67c4c882e1e

-- 
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