[mod_redirect,mod_rewrite] base64url encoding opt

Provide means to encode redirect and rewrite backreference substitutions

  %{encb64u:...} encode to base64url characters (no-padding)
  %{decb64u:...} decode from base64url characters

src/Makefile.am

@@ -524,7 +524,7 @@ t_test_buffer_LDADD = $(LIBUNWIND_LIBS)
 t_test_base64_SOURCES = t/test_base64.c base64.c buffer.c
 t_test_base64_LDADD = $(LIBUNWIND_LIBS)
 
-t_test_burl_SOURCES = t/test_burl.c burl.c buffer.c
+t_test_burl_SOURCES = t/test_burl.c burl.c buffer.c base64.c
 t_test_burl_LDADD = $(LIBUNWIND_LIBS)
 
 t_test_configfile_SOURCES = t/test_configfile.c buffer.c array.c data_config.c data_string.c http_kv.c vector.c log.c sock_addr.c

src/burl.c

@@ -4,6 +4,7 @@
 #include <string.h>
 
 #include "buffer.h"
+#include "base64.h"
 
 static const char hex_chars_uc[] = "0123456789ABCDEF";
 
@@ -493,6 +494,13 @@ void burl_append (buffer * const b, const char * const str, const size_t len, co
     else if (flags & BURL_ENCODE_PSNDE) {
         burl_append_encode_psnde(b, str, len);
     }
+    else if (flags & BURL_ENCODE_B64U) {
+        const unsigned char *s = (const unsigned char *)str;
+        buffer_append_base64_encode_no_padding(b, s, len, BASE64_URL);
+    }
+    else if (flags & BURL_DECODE_B64U) {
+        buffer_append_base64_decode(b, str, len, BASE64_URL);
+    }
 
     /* note: not normalizing str, which could come from arbitrary header,
      * so it is possible that alpha chars are percent-encoded upper/lowercase */

src/burl.h

@@ -37,6 +37,8 @@ enum burl_recoding_e {
  ,BURL_ENCODE_ALL      = 0x0008
  ,BURL_ENCODE_NDE      = 0x0010 /* encode delims, but no-double-encode (NDE) */
  ,BURL_ENCODE_PSNDE    = 0x0020 /* similar to NDE, but preserve literal slash */
+ ,BURL_ENCODE_B64U     = 0x0040
+ ,BURL_DECODE_B64U     = 0x0080
 };
 
 void burl_append (buffer * const b, const char * const str, const size_t len, const int flags);

src/keyvalue.c

@@ -234,6 +234,16 @@ static int pcre_keyvalue_buffer_subst_ext(buffer *b, const char *pattern, const
             p+=3;
             break;
         }
+        else if (p[0] == 'e' && p[1] == 'n' && p[2] == 'c'
+                 && 0 == strncmp((const char *)p+3, "b64u:", 5)) {
+            flags |= BURL_ENCODE_B64U;
+            p+=8;
+        }
+        else if (p[0] == 'd' && p[1] == 'e' && p[2] == 'c'
+                 && 0 == strncmp((const char *)p+3, "b64u:", 5)) {
+            flags |= BURL_DECODE_B64U;
+            p+=8;
+        }
         else ++p;  /* skip unrecognized char */
     }
     if (*p == '\0') return -1;