UA: align with compat spec

See: https://compat.spec.whatwg.org/#ua-string-section

Force desktop sites on Linux by claiming to be running under X11
(Linux is otherwise considered a mobile OS).

3 files changed, 23 insertions, 16 deletions

diff --git a/Makefile.defaults b/Makefile.defaults
index edf491a6f..85be74802 100644
--- a/Makefile.defaults
+++ b/Makefile.defaults
@@ -101,10 +101,11 @@ NETSURF_USE_UTF8PROC := YES
 # Valid options: YES, NO
 NETSURF_STRIP_BINARY := NO
 
-# Template used for constructing the User Agent: string.  The first two
-# replacements are major/minor version, next is OS.
-# Please don't be tempted to mention Mozilla here!  Let's let that lie die.
-NETSURF_UA_FORMAT_STRING := "NetSurf/%d.%d (%s)"
+# Template used for constructing the User Agent: string.  The first
+# replacement is OS, the next two are major/minor version.
+# Note that the "Mozilla/5.0" prefix is a requirement to enable modern
+# web standards on many websites. It should not be removed or modified.
+NETSURF_UA_FORMAT_STRING := "Mozilla/5.0 (%s) NetSurf/%d.%d"
 
 # Default home page, if one is not defined by the user.  Note that this
 # option does not apply to the RISC OS version, as it has its own local
diff --git a/docs/PACKAGING-GTK b/docs/PACKAGING-GTK
index 4eab25b96..b81bc6162 100644
--- a/docs/PACKAGING-GTK
+++ b/docs/PACKAGING-GTK
@@ -64,18 +64,19 @@
 ===================
 
   You may also want to change NetSurf's user agent string to include the
-  name of your distribution.  The user agent string is build by a function
+  name of your distribution.  The user agent string is built by a function
   kept in utils/useragent.c - you'll want to change the macro called
   NETSURF_UA_FORMAT_STRING.  It's processed via sprintf, so keep that in
-  mind when changing it.  The first two printf parameters are major and minor
-  version numbers, the second two are OS name (uname -s) and architecture
-  (uname -m).  You might want change this to something like:
+  mind when changing it.  The first format parameter is the OS name (uname -s)
+  and the remainder are major and minor version numbers.  You might want
+  to change this to something like:
 
-      "NetSurf/%d.%d (%s; %s; Debian GNU/Linux)"
+      "Mozilla/5.0 (%s; Debian GNU/Linux) NetSurf/%d.%d"
 
-  or similar.  Please don't be tempted to mention Mozilla or similar - let's
-  let that lie die.
+  or similar.
 
+  Note that the "Mozilla/5.0" prefix is a requirement to enable modern
+  web standards on many websites. It should not be removed or modified.
 
   Home page URL
 ===============
diff --git a/utils/useragent.c b/utils/useragent.c
index 3d93a97b2..547999c7c 100644
--- a/utils/useragent.c
+++ b/utils/useragent.c
@@ -19,6 +19,7 @@
 
 #include <stdio.h>
 #include <stdlib.h>
+#include <string.h>
 
 #include "utils/config.h"
 #include "utils/utsname.h"
@@ -29,7 +30,7 @@
 static const char *core_user_agent_string = NULL;
 
 #ifndef NETSURF_UA_FORMAT_STRING
-#define NETSURF_UA_FORMAT_STRING "NetSurf/%d.%d (%s)"
+#define NETSURF_UA_FORMAT_STRING "Mozilla/5.0 (%s) NetSurf/%d.%d"
 #endif
 
 /**
@@ -46,12 +47,16 @@ user_agent_build_string(void)
 
         if (uname(&un) >= 0) {
                 sysname = un.sysname;
+                if (strcmp(sysname, "Linux") == 0) {
+			/* Force desktop, not mobile */
+                        sysname = "X11; Linux";
+                }
         }
 
         len = snprintf(NULL, 0, NETSURF_UA_FORMAT_STRING,
+                       sysname,
                        netsurf_version_major,
-                       netsurf_version_minor,
-                       sysname);
+                       netsurf_version_minor);
         ua_string = malloc(len + 1);
         if (!ua_string) {
                 /** \todo this needs handling better */
@@ -59,9 +64,9 @@ user_agent_build_string(void)
         }
         snprintf(ua_string, len + 1,
                  NETSURF_UA_FORMAT_STRING,
+                 sysname,
                  netsurf_version_major,
-                 netsurf_version_minor,
-                 sysname);
+                 netsurf_version_minor);
 
         core_user_agent_string = ua_string;