src: Support rel with quoted value in Link header parser

src/http2.cc

@@ -741,6 +741,54 @@ parse_next_link_header_once(const char *first, const char *last) {
     }
     // we expect link-param
 
+    // rel can take several relations using quoted form.
+    static const char PLP[] = "rel=\"";
+    static const size_t PLPLEN = sizeof(PLP) - 1;
+
+    static const char PLT[] = "preload";
+    static const size_t PLTLEN = sizeof(PLT) - 1;
+    if (first + PLPLEN < last && *(first + PLPLEN - 1) == '"' &&
+        std::equal(PLP, PLP + PLPLEN, first)) {
+      // we have to search preload in whitespace separated list:
+      // rel="preload something http://example.org/foo"
+      first += PLPLEN;
+      auto start = first;
+      for (; first != last;) {
+        if (*first != ' ' && *first != '"') {
+          ++first;
+          continue;
+        }
+
+        if (start == first) {
+          return {{{0, 0}}, last};
+        }
+
+        if (!ok && start + PLTLEN == first && *(start + PLTLEN - 1) == 'd' &&
+            std::equal(PLT, PLT + PLTLEN, start)) {
+          ok = true;
+        }
+
+        if (*first == '"') {
+          break;
+        }
+        first = skip_lws(first, last);
+        start = first;
+      }
+      if (first == last) {
+        return {{{0, 0}}, first};
+      }
+      assert(*first == '"');
+      ++first;
+      if (first == last || *first == ',') {
+        goto almost_done;
+      }
+      if (*first == ';') {
+        ++first;
+        // parse next link-param
+        continue;
+      }
+      return {{{0, 0}}, last};
+    }
     // we are only interested in rel=preload parameter.  Others are
     // simply skipped.
     static const char PL[] = "rel=preload";

src/http2_test.cc

@@ -489,6 +489,110 @@ void test_http2_parse_link_header(void) {
     auto res = http2::parse_link_header(s, sizeof(s) - 1);
     CU_ASSERT(0 == res.size());
   }
+  {
+    // preload in relation-types list
+    const char s[] = R"(<url>; rel="preload")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // preload in relation-types list followed by another parameter
+    const char s[] = R"(<url>; rel="preload foo")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // preload in relation-types list following another parameter
+    const char s[] = R"(<url>; rel="foo preload")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // preload in relation-types list between other parameters
+    const char s[] = R"(<url>; rel="foo preload bar")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // preload in relation-types list between other parameters
+    const char s[] = R"(<url>; rel="foo   preload   bar")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // no preload in relation-types list
+    const char s[] = R"(<url>; rel="foo")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // no preload in relation-types list, multiple unrelated elements.
+    const char s[] = R"(<url>; rel="foo bar")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // preload in relation-types list, followed by another link-value.
+    const char s[] = R"(<url>; rel="preload", <url>)";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // preload in relation-types list, following another link-value.
+    const char s[] = R"(<url>, <url>; rel="preload")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[8], &s[11]) == res[0].uri);
+  }
+  {
+    // preload in relation-types list, followed by another link-param.
+    const char s[] = R"(<url>; rel="preload"; as="font")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // preload in relation-types list, followed by character other
+    // than ';' or ','
+    const char s[] = R"(<url>; rel="preload".)";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // preload in relation-types list, followed by ';' but it
+    // terminates input
+    const char s[] = R"(<url>; rel="preload";)";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // preload in relation-types list, followed by ',' but it
+    // terminates input
+    const char s[] = R"(<url>; rel="preload",)";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(1 == res.size());
+    CU_ASSERT(std::make_pair(&s[1], &s[4]) == res[0].uri);
+  }
+  {
+    // preload in relation-types list but there is preceding white
+    // space.
+    const char s[] = R"(<url>; rel=" preload")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
+  {
+    // preload in relation-types list but there is trailing white
+    // space.
+    const char s[] = R"(<url>; rel="preload ")";
+    auto res = http2::parse_link_header(s, sizeof(s) - 1);
+    CU_ASSERT(0 == res.size());
+  }
 }
 
 void test_http2_path_join(void) {