CURLOPT_DEFAULT_PROTOCOL: added

- Add new option CURLOPT_DEFAULT_PROTOCOL to allow specifying a default
protocol for schemeless URLs.

- Add new tool option --proto-default to expose
CURLOPT_DEFAULT_PROTOCOL.

In the case of schemeless URLs libcurl will behave in this way:

When the option is used libcurl will use the supplied default.

When the option is not used, libcurl will follow its usual plan of
guessing from the hostname and falling back to 'http'.

2 files changed, 29 insertions, 19 deletions

diff --git a/lib/url.c b/lib/url.c
index 406c1f02c..d572f0195 100644
--- a/lib/url.c
+++ b/lib/url.c
@@ -2441,6 +2441,12 @@ CURLcode Curl_setopt(struct SessionHandle *data, CURLoption option,
     data->set.redir_protocols = va_arg(param, long);
     break;
 
+  case CURLOPT_DEFAULT_PROTOCOL:
+    /* Set the protocol to use when the URL doesn't include any protocol */
+    result = setstropt(&data->set.str[STRING_DEFAULT_PROTOCOL],
+                       va_arg(param, char *));
+    break;
+
   case CURLOPT_MAIL_FROM:
     /* Set the SMTP mail originator */
     result = setstropt(&data->set.str[STRING_MAIL_FROM],
@@ -4028,27 +4034,30 @@ static CURLcode parseurlandfillconn(struct SessionHandle *data,
       }
 
       /*
-       * Since there was no protocol part specified, we guess what protocol it
-       * is based on the first letters of the server name.
+       * Since there was no protocol part specified in the URL use the
+       * user-specified default protocol. If we weren't given a default make a
+       * guess by matching some protocols against the host's outermost
+       * sub-domain name. Finally if there was no match use HTTP.
        */
 
-      /* Note: if you add a new protocol, please update the list in
-       * lib/version.c too! */
-
-      if(checkprefix("FTP.", conn->host.name))
-        protop = "ftp";
-      else if(checkprefix("DICT.", conn->host.name))
-        protop = "DICT";
-      else if(checkprefix("LDAP.", conn->host.name))
-        protop = "LDAP";
-      else if(checkprefix("IMAP.", conn->host.name))
-        protop = "IMAP";
-      else if(checkprefix("SMTP.", conn->host.name))
-        protop = "smtp";
-      else if(checkprefix("POP3.", conn->host.name))
-        protop = "pop3";
-      else {
-        protop = "http";
+      protop = data->set.str[STRING_DEFAULT_PROTOCOL];
+      if(!protop) {
+        /* Note: if you add a new protocol, please update the list in
+         * lib/version.c too! */
+        if(checkprefix("FTP.", conn->host.name))
+          protop = "ftp";
+        else if(checkprefix("DICT.", conn->host.name))
+          protop = "DICT";
+        else if(checkprefix("LDAP.", conn->host.name))
+          protop = "LDAP";
+        else if(checkprefix("IMAP.", conn->host.name))
+          protop = "IMAP";
+        else if(checkprefix("SMTP.", conn->host.name))
+          protop = "smtp";
+        else if(checkprefix("POP3.", conn->host.name))
+          protop = "pop3";
+        else
+          protop = "http";
       }
 
       *prot_missing = TRUE; /* not given in URL */
diff --git a/lib/urldata.h b/lib/urldata.h
index b1c2056c5..3207e61e9 100644
--- a/lib/urldata.h
+++ b/lib/urldata.h
@@ -1350,6 +1350,7 @@ enum dupstring {
   STRING_COOKIE,          /* HTTP cookie string to send */
   STRING_COOKIEJAR,       /* dump all cookies to this file */
   STRING_CUSTOMREQUEST,   /* HTTP/FTP/RTSP request/method to use */
+  STRING_DEFAULT_PROTOCOL, /* Protocol to use when the URL doesn't specify */
   STRING_DEVICE,          /* local network interface/address to use */
   STRING_ENCODING,        /* Accept-Encoding string */
   STRING_FTP_ACCOUNT,     /* ftp account data */