Optionally compress large responses, if the browser accepts deflate compression. This mainly improves start up time.

git-svn-id: https://shellinabox.googlecode.com/svn/trunk@142 0da03de8-d603-11dd-86c2-0f8696b7b6f9

ChangeLog

@@ -1,3 +1,8 @@
+2009-07-08  Markus Gutschke  <markus@shellinabox.com>
+
+	* Optionally compress large responses, if the browser accepts
+	deflate compression. This mainly improves start up time.
+
 2009-07-06  Markus Gutschke  <markus@shellinabox.com>
 
 	* Making it easier to host the terminal on non-root URLs by always

config.h

@@ -106,6 +106,9 @@
 /* Define to 1 if you have the <utmp.h> header file. */
 #define HAVE_UTMP_H 1
 
+/* Define to 1 if zlib development files are installed */
+#define HAVE_ZLIB 1
+
 /* Define to the sub-directory in which libtool stores uninstalled libraries.
    */
 #define LT_OBJDIR ".libs/"
@@ -132,7 +135,7 @@
 #define STDC_HEADERS 1
 
 /* Most recent revision number in the version control system */
-#define VCS_REVISION "141"
+#define VCS_REVISION "142"
 
 /* Version number of package */
 #define VERSION "2.9"

config.h.in

@@ -105,6 +105,9 @@
 /* Define to 1 if you have the <utmp.h> header file. */
 #undef HAVE_UTMP_H
 
+/* Define to 1 if zlib development files are installed */
+#undef HAVE_ZLIB
+
 /* Define to the sub-directory in which libtool stores uninstalled libraries.
    */
 #undef LT_OBJDIR

configure.ac

@@ -2,7 +2,7 @@ AC_PREREQ(2.57)
 
 dnl This is the one location where the authoritative version number is stored
 AC_INIT(shellinabox, 2.9, markus@shellinabox.com)
-VCS_REVISION=141
+VCS_REVISION=142
 AC_SUBST(VCS_REVISION)
 AC_DEFINE_UNQUOTED(VCS_REVISION, "${VCS_REVISION}",
                    [Most recent revision number in the version control system])
@@ -122,6 +122,12 @@ if test "x$enable_runtime_loading" == xno; then
   fi
 fi
 
+AC_CHECK_LIB(z, deflate, [
+  AC_CHECK_HEADER(zlib.h, [LIBS="-lz $LIBS"
+                           AC_DEFINE(HAVE_ZLIB, 1,
+                           Define to 1 if zlib development files are installed)
+])])
+
 dnl Generate output files
 AC_CONFIG_FILES([Makefile])
 AC_OUTPUT

demo/vt100.js

@@ -1693,7 +1693,7 @@ VT100.prototype.toggleBell = function() {
 };
 
 VT100.prototype.about = function() {
-  alert("VT100 Terminal Emulator " + "2.9 (revision 141)" +
+  alert("VT100 Terminal Emulator " + "2.9 (revision 142)" +
         "\nCopyright 2008-2009 by Markus Gutschke\n" +
         "For more information check http://shellinabox.com");
 };

libhttp/httpconnection.c

@@ -48,6 +48,7 @@
 
 #include <errno.h>
 #include <arpa/inet.h>
+#include <math.h>
 #include <netdb.h>
 #include <netinet/in.h>
 #include <stdio.h>
@@ -58,6 +59,10 @@
 #include <sys/types.h>
 #include <unistd.h>
 
+#ifdef HAVE_ZLIB
+#include <zlib.h>
+#endif
+
 #ifdef HAVE_STRLCAT
 #define strncat(a,b,c) ({ char *_a = (a); strlcat(_a, (b), (c)+1); _a; })
 #endif
@@ -414,15 +419,87 @@ void deleteHttpConnection(struct HttpConnection *http) {
   free(http);
 }
 
+#ifdef HAVE_ZLIB
+static int httpAcceptsEncoding(struct HttpConnection *http,
+                               const char *encoding) {
+  int encodingLength  = strlen(encoding);
+  const char *accepts = getFromHashMap(&http->header, "accept-encoding");
+  if (!accepts) {
+    return 0;
+  }
+  double all          = -1.0;
+  double match        = -1.0;
+  while (*accepts) {
+    while (*accepts == ' ' || *accepts == '\t' ||
+           *accepts == '\r' || *accepts == '\n') {
+      accepts++;
+    }
+    const char *ptr   = accepts;
+    while (*ptr && *ptr != ',' && *ptr != ';' &&
+           *ptr != ' ' && *ptr != '\t' &&
+           *ptr != '\r' && *ptr != '\n') {
+      ptr++;
+    }
+    int isAll         = ptr - accepts == 1 && *accepts == '*';
+    int isMatch       = ptr - accepts == encodingLength &&
+                        !strncasecmp(accepts, encoding, encodingLength);
+    while (*ptr && *ptr != ';' && *ptr != ',') {
+      ptr++;
+    }
+    double val        = 1.0;
+    if (*ptr == ';') {
+      ptr++;
+      while (*ptr == ' ' || *ptr == '\t' || *ptr == '\r' || *ptr == '\n') {
+        ptr++;
+      }
+      if ((*ptr | 0x20) == 'q') {
+        ptr++;
+        while (*ptr == ' ' || *ptr == '\t' || *ptr == '\r' || *ptr == '\n') {
+          ptr++;
+        }
+        if (*ptr == '=') {
+          val         = strtod(ptr + 1, (char **)&ptr);
+        }
+      }
+    }
+    if (isnan(val) || val == -HUGE_VAL || val < 0) {
+      val             = 0;
+    } else if (val == HUGE_VAL || val > 1.0) {
+      val             = 1.0;
+    }
+    if (isAll) {
+      all             = val;
+    } else if (isMatch) {
+      match           = val;
+    }
+    while (*ptr && *ptr != ',') {
+      ptr++;
+    }
+    while (*ptr == ',') {
+      ptr++;
+    }
+    accepts           = ptr;
+  }
+  if (match >= 0.0) {
+    return match > 0.0;
+  } else {
+    return all > 0.0;
+  }
+}
+#endif
+
 void httpTransfer(struct HttpConnection *http, char *msg, int len) {
   check(msg);
   check(len >= 0);
 
+  int compress              = 0;
+  char *contentLength       = NULL;
   if (!http->totalWritten) {
     // Perform some basic sanity checks. This does not necessarily catch all
     // possible problems, though.
     int l                   = len;
-    for (char *eol, *lastLine = NULL, *line = msg;
+    char *line              = msg;
+    for (char *eol, *lastLine = NULL;
          l > 0 && (eol = memchr(line, '\n', l)) != NULL; ) {
       // All lines end in CR LF
       check(eol[-1] == '\r');
@@ -443,21 +520,94 @@ void httpTransfer(struct HttpConnection *http, char *msg, int len) {
         }
         check(i > 1);
       } else if (line + 1 == eol) {
-        // Don't send any data with HEAD requests
+        // Found the end of the headers.
-        check(l == 2 || strcmp(http->method, "HEAD"));
+
+        // Check that we don't send any data with HEAD requests
+        int isHead          = !strcmp(http->method, "HEAD");
+        check(l == 2 || !isHead);
+
+        #ifdef HAVE_ZLIB
+        // Compress replies that might exceed the size of a single IP packet
+        compress            = !isHead &&
+                              !http->isPartialReply &&
+                              len > 1400 &&
+                              httpAcceptsEncoding(http, "deflate");
+        #endif
         break;
       } else {
         // Header lines either contain a colon, or they are continuation
         // lines
         if (*line != ' ' && *line != '\t') {
           check(memchr(line, ':', eol - line));
+
+          // Remember where we saw the Content-Length header. We need to edit
+          // it, if we end up sending compressed data
+          if (!strncasecmp(line, "Content-Length:", 15)) {
+            contentLength   = line;
+          }
         }
       }
       lastLine              = line;
       l                    -= eol - line + 1;
       line                  = eol + 1;
     }
+
+    if (compress) {
+      #ifdef HAVE_ZLIB
+      // Create a copy of msg, and edit existing Content-Length line
+      // out of header.
+      char *compressed, *ptr;
+      check(compressed      = malloc(len + 100));
+      if (contentLength) {
+        memcpy(compressed, msg, contentLength - msg);
+        char *part2         = strchr(contentLength, '\n');
+        check(part2++);
+        memcpy(compressed + (contentLength - msg), part2, line - part2);
+        ptr                 = compressed + (contentLength - msg) +
+                                           (line - part2);
+      } else {
+        memcpy(compressed, msg, line - msg);
+        ptr                 = compressed + (line - msg);
       }
+
+      // Add new Content-Encoding and new Content-Length lines. Leave enough
+      // space to later edit the actual length back in.
+      memcpy(ptr,
+             "Content-Encoding: deflate\r\n"
+             "Content-Length:                    \r\n\r\n",
+             66);
+      contentLength         = ptr + 42;
+      ptr                  += 66;
+      
+      // Compress the message
+      z_stream strm         = { .zalloc    = Z_NULL,
+                                .zfree     = Z_NULL,
+                                .opaque    = Z_NULL,
+                                .avail_in  = l - 2,
+                                .next_in   = (unsigned char *)line + 2,
+                                .avail_out = len - (ptr - compressed),
+                                .next_out  = (unsigned char *)ptr
+                              };
+      if (deflateInit(&strm, Z_DEFAULT_COMPRESSION) == Z_OK) {
+        if (deflate(&strm, Z_FINISH) == Z_STREAM_END) {
+          // Compression was successful and resulted in reduction in size
+          debug("Compressed response from %d to %d", len, len-strm.avail_out);
+          free(msg);
+          msg               = compressed;
+          len              -= strm.avail_out;
+          snprintf(contentLength, 21, "%20d", len - (ptr - compressed));
+          contentLength[20] = '\r';
+        } else {
+          free(compressed);
+        }
+        deflateEnd(&strm);
+      } else {
+        free(compressed);
+      }
+      #endif
+    }
+  }
+
   http->totalWritten       += len;
   if (!len) {
     free(msg);
@@ -479,9 +629,9 @@ void httpTransfer(struct HttpConnection *http, char *msg, int len) {
     http->msgLength         = len;
   }
 
-  // Internet Explorer prior to version 7 has a bug when send XMLHttpRequests
+  // Internet Explorer prior to version 7 has a bug when sending
-  // over HTTPS that go through a proxy. It won't see the reply until we
+  // XMLHttpRequests over HTTPS that go through a proxy. It won't see the
-  // close the connection.
+  // reply until we close the connection.
   int ieBug                 = 0;
   if (http->sslHndl) {
     const char *userAgent   = getFromHashMap(&http->header, "user-agent");

shellinabox/shell_in_a_box.js

@@ -355,7 +355,7 @@ ShellInABox.prototype.extendContextMenu = function(entries, actions) {
 };
 
 ShellInABox.prototype.about = function() {
-  alert("Shell In A Box version " + "2.9 (revision 141)" +
+  alert("Shell In A Box version " + "2.9 (revision 142)" +
         "\nCopyright 2008-2009 by Markus Gutschke\n" +
         "For more information check http://shellinabox.com" +
         (typeof serverSupportsSSL != 'undefined' && serverSupportsSSL ?

shellinabox/vt100.js

@@ -1693,7 +1693,7 @@ VT100.prototype.toggleBell = function() {
 };
 
 VT100.prototype.about = function() {
-  alert("VT100 Terminal Emulator " + "2.9 (revision 141)" +
+  alert("VT100 Terminal Emulator " + "2.9 (revision 142)" +
         "\nCopyright 2008-2009 by Markus Gutschke\n" +
         "For more information check http://shellinabox.com");
 };