| // Copyright 2019 The Chromium Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style license that can be |
| // found in the LICENSE file. |
| |
| #ifndef QUICHE_COMMON_STRUCTURED_HEADERS_H_ |
| #define QUICHE_COMMON_STRUCTURED_HEADERS_H_ |
| |
| #include <cstddef> |
| #include <cstdint> |
| #include <map> |
| #include <optional> |
| #include <string> |
| #include <tuple> |
| #include <utility> |
| #include <vector> |
| |
| #include "absl/strings/string_view.h" |
| #include "absl/types/variant.h" |
| #include "quiche/common/platform/api/quiche_export.h" |
| #include "quiche/common/platform/api/quiche_logging.h" |
| |
| namespace quiche { |
| namespace structured_headers { |
| |
| // This file implements parsing of HTTP structured headers, as defined in |
| // RFC8941 (https://www.rfc-editor.org/rfc/rfc8941.html). For compatibility with |
| // the shipped implementation of Web Packaging, this file also supports a |
| // previous revision of the standard, referred to here as "Draft 9". |
| // (https://datatracker.ietf.org/doc/draft-ietf-httpbis-header-structure/09/) |
| // |
| // The major difference between the two revisions is in the various list |
| // formats: Draft 9 describes "parameterised lists" and "lists-of-lists", while |
| // the final RFC uses a single "list" syntax, whose members may be inner lists. |
| // There should be no ambiguity, however, as the code which calls this parser |
| // should be expecting only a single type for a given header. |
| // |
| // References within the code are tagged with either [SH09] or [RFC8941], |
| // depending on which revision they refer to. |
| // |
| // Currently supported data types are: |
| // Item: |
| // integer: 123 |
| // string: "abc" |
| // token: abc |
| // byte sequence: *YWJj* |
| // Parameterised list: abc_123;a=1;b=2; cdef_456, ghi;q="9";r="w" |
| // List-of-lists: "foo";"bar", "baz", "bat"; "one" |
| // List: "foo", "bar", "It was the best of times." |
| // ("foo" "bar"), ("baz"), ("bat" "one"), () |
| // abc;a=1;b=2; cde_456, (ghi jkl);q="9";r=w |
| // Dictionary: a=(1 2), b=3, c=4;aa=bb, d=(5 6);valid=?0 |
| // |
| // Functions are provided to parse each of these, which are intended to be |
| // called with the complete value of an HTTP header (that is, any |
| // sub-structure will be handled internally by the parser; the exported |
| // functions are not intended to be called on partial header strings.) Input |
| // values should be ASCII byte strings (non-ASCII characters should not be |
| // present in Structured Header values, and will cause the entire header to fail |
| // to parse.) |
| |
| class QUICHE_EXPORT Item { |
| public: |
| enum ItemType { |
| kNullType, |
| kIntegerType, |
| kDecimalType, |
| kStringType, |
| kTokenType, |
| kByteSequenceType, |
| kBooleanType |
| }; |
| Item(); |
| explicit Item(int64_t value); |
| explicit Item(double value); |
| explicit Item(bool value); |
| |
| // Constructors for string-like items: Strings, Tokens and Byte Sequences. |
| Item(const char* value, Item::ItemType type = kStringType); |
| Item(std::string value, Item::ItemType type = kStringType); |
| |
| QUICHE_EXPORT friend bool operator==(const Item& lhs, const Item& rhs); |
| inline friend bool operator!=(const Item& lhs, const Item& rhs) { |
| return !(lhs == rhs); |
| } |
| |
| bool is_null() const { return Type() == kNullType; } |
| bool is_integer() const { return Type() == kIntegerType; } |
| bool is_decimal() const { return Type() == kDecimalType; } |
| bool is_string() const { return Type() == kStringType; } |
| bool is_token() const { return Type() == kTokenType; } |
| bool is_byte_sequence() const { return Type() == kByteSequenceType; } |
| bool is_boolean() const { return Type() == kBooleanType; } |
| |
| int64_t GetInteger() const { |
| const auto* value = absl::get_if<int64_t>(&value_); |
| QUICHE_CHECK(value); |
| return *value; |
| } |
| double GetDecimal() const { |
| const auto* value = absl::get_if<double>(&value_); |
| QUICHE_CHECK(value); |
| return *value; |
| } |
| bool GetBoolean() const { |
| const auto* value = absl::get_if<bool>(&value_); |
| QUICHE_CHECK(value); |
| return *value; |
| } |
| // TODO(iclelland): Split up accessors for String, Token and Byte Sequence. |
| const std::string& GetString() const { |
| struct Visitor { |
| const std::string* operator()(const absl::monostate&) { return nullptr; } |
| const std::string* operator()(const int64_t&) { return nullptr; } |
| const std::string* operator()(const double&) { return nullptr; } |
| const std::string* operator()(const std::string& value) { return &value; } |
| const std::string* operator()(const bool&) { return nullptr; } |
| }; |
| const std::string* value = absl::visit(Visitor(), value_); |
| QUICHE_CHECK(value); |
| return *value; |
| } |
| |
| // Transfers ownership of the underlying String, Token, or Byte Sequence. |
| std::string TakeString() && { |
| struct Visitor { |
| std::string* operator()(absl::monostate&) { return nullptr; } |
| std::string* operator()(int64_t&) { return nullptr; } |
| std::string* operator()(double&) { return nullptr; } |
| std::string* operator()(std::string& value) { return &value; } |
| std::string* operator()(bool&) { return nullptr; } |
| }; |
| std::string* value = absl::visit(Visitor(), value_); |
| QUICHE_CHECK(value); |
| return std::move(*value); |
| } |
| |
| ItemType Type() const { return static_cast<ItemType>(value_.index()); } |
| |
| private: |
| absl::variant<absl::monostate, int64_t, double, std::string, std::string, |
| std::string, bool> |
| value_; |
| }; |
| |
| // Returns a human-readable representation of an ItemType. |
| QUICHE_EXPORT absl::string_view ItemTypeToString(Item::ItemType type); |
| |
| // Returns `true` if the string is a valid Token value. |
| QUICHE_EXPORT bool IsValidToken(absl::string_view str); |
| |
| // Holds a ParameterizedIdentifier (draft 9 only). The contained Item must be a |
| // Token, and there may be any number of parameters. Parameter ordering is not |
| // significant. |
| struct QUICHE_EXPORT ParameterisedIdentifier { |
| using Parameters = std::map<std::string, Item>; |
| |
| Item identifier; |
| Parameters params; |
| |
| ParameterisedIdentifier(); |
| ParameterisedIdentifier(const ParameterisedIdentifier&); |
| ParameterisedIdentifier& operator=(const ParameterisedIdentifier&); |
| ParameterisedIdentifier(Item, Parameters); |
| ~ParameterisedIdentifier(); |
| }; |
| |
| inline bool operator==(const ParameterisedIdentifier& lhs, |
| const ParameterisedIdentifier& rhs) { |
| return std::tie(lhs.identifier, lhs.params) == |
| std::tie(rhs.identifier, rhs.params); |
| } |
| |
| using Parameters = std::vector<std::pair<std::string, Item>>; |
| |
| struct QUICHE_EXPORT ParameterizedItem { |
| Item item; |
| Parameters params; |
| |
| ParameterizedItem(); |
| ParameterizedItem(const ParameterizedItem&); |
| ParameterizedItem& operator=(const ParameterizedItem&); |
| ParameterizedItem(Item, Parameters); |
| ~ParameterizedItem(); |
| }; |
| |
| inline bool operator==(const ParameterizedItem& lhs, |
| const ParameterizedItem& rhs) { |
| return std::tie(lhs.item, lhs.params) == std::tie(rhs.item, rhs.params); |
| } |
| |
| inline bool operator!=(const ParameterizedItem& lhs, |
| const ParameterizedItem& rhs) { |
| return !(lhs == rhs); |
| } |
| |
| // Holds a ParameterizedMember, which may be either an single Item, or an Inner |
| // List of ParameterizedItems, along with any number of parameters. Parameter |
| // ordering is significant. |
| struct QUICHE_EXPORT ParameterizedMember { |
| std::vector<ParameterizedItem> member; |
| // If false, then |member| should only hold one Item. |
| bool member_is_inner_list = false; |
| |
| Parameters params; |
| |
| ParameterizedMember(); |
| ParameterizedMember(const ParameterizedMember&); |
| ParameterizedMember& operator=(const ParameterizedMember&); |
| ParameterizedMember(std::vector<ParameterizedItem>, bool member_is_inner_list, |
| Parameters); |
| // Shorthand constructor for a member which is an inner list. |
| ParameterizedMember(std::vector<ParameterizedItem>, Parameters); |
| // Shorthand constructor for a member which is a single Item. |
| ParameterizedMember(Item, Parameters); |
| ~ParameterizedMember(); |
| }; |
| |
| inline bool operator==(const ParameterizedMember& lhs, |
| const ParameterizedMember& rhs) { |
| return std::tie(lhs.member, lhs.member_is_inner_list, lhs.params) == |
| std::tie(rhs.member, rhs.member_is_inner_list, rhs.params); |
| } |
| |
| using DictionaryMember = std::pair<std::string, ParameterizedMember>; |
| |
| // Structured Headers RFC8941 Dictionary. |
| class QUICHE_EXPORT Dictionary { |
| public: |
| using iterator = std::vector<DictionaryMember>::iterator; |
| using const_iterator = std::vector<DictionaryMember>::const_iterator; |
| |
| Dictionary(); |
| Dictionary(const Dictionary&); |
| explicit Dictionary(std::vector<DictionaryMember> members); |
| ~Dictionary(); |
| Dictionary& operator=(const Dictionary&) = default; |
| iterator begin(); |
| const_iterator begin() const; |
| iterator end(); |
| const_iterator end() const; |
| |
| // operator[](size_t) and at(size_t) will both abort the program in case of |
| // out of bounds access. |
| ParameterizedMember& operator[](std::size_t idx); |
| const ParameterizedMember& operator[](std::size_t idx) const; |
| ParameterizedMember& at(std::size_t idx); |
| const ParameterizedMember& at(std::size_t idx) const; |
| |
| // Consistent with std::map, if |key| does not exist in the Dictionary, then |
| // operator[](absl::string_view) will create an entry for it, but at() will |
| // abort the entire program. |
| ParameterizedMember& operator[](absl::string_view key); |
| ParameterizedMember& at(absl::string_view key); |
| const ParameterizedMember& at(absl::string_view key) const; |
| |
| bool empty() const; |
| std::size_t size() const; |
| bool contains(absl::string_view key) const; |
| friend bool operator==(const Dictionary& lhs, const Dictionary& rhs); |
| friend bool operator!=(const Dictionary& lhs, const Dictionary& rhs); |
| |
| private: |
| // Uses a vector to hold pairs of key and dictionary member. This makes |
| // look up by index and serialization much easier. |
| std::vector<DictionaryMember> members_; |
| }; |
| |
| inline bool operator==(const Dictionary& lhs, const Dictionary& rhs) { |
| return lhs.members_ == rhs.members_; |
| } |
| |
| inline bool operator!=(const Dictionary& lhs, const Dictionary& rhs) { |
| return !(lhs == rhs); |
| } |
| |
| // Structured Headers Draft 09 Parameterised List. |
| using ParameterisedList = std::vector<ParameterisedIdentifier>; |
| // Structured Headers Draft 09 List of Lists. |
| using ListOfLists = std::vector<std::vector<Item>>; |
| // Structured Headers RFC8941 List. |
| using List = std::vector<ParameterizedMember>; |
| |
| // Returns the result of parsing the header value as an Item, if it can be |
| // parsed as one, or nullopt if it cannot. Note that this uses the Draft 15 |
| // parsing rules, and so applies tighter range limits to integers. |
| QUICHE_EXPORT std::optional<ParameterizedItem> ParseItem(absl::string_view str); |
| |
| // Returns the result of parsing the header value as an Item with no parameters, |
| // or nullopt if it cannot. Note that this uses the Draft 15 parsing rules, and |
| // so applies tighter range limits to integers. |
| QUICHE_EXPORT std::optional<Item> ParseBareItem(absl::string_view str); |
| |
| // Returns the result of parsing the header value as a Parameterised List, if it |
| // can be parsed as one, or nullopt if it cannot. Note that parameter keys will |
| // be returned as strings, which are guaranteed to be ASCII-encoded. List items, |
| // as well as parameter values, will be returned as Items. This method uses the |
| // Draft 09 parsing rules for Items, so integers have the 64-bit int range. |
| // Structured-Headers Draft 09 only. |
| QUICHE_EXPORT std::optional<ParameterisedList> ParseParameterisedList( |
| absl::string_view str); |
| |
| // Returns the result of parsing the header value as a List of Lists, if it can |
| // be parsed as one, or nullopt if it cannot. Inner list items will be returned |
| // as Items. This method uses the Draft 09 parsing rules for Items, so integers |
| // have the 64-bit int range. |
| // Structured-Headers Draft 09 only. |
| QUICHE_EXPORT std::optional<ListOfLists> ParseListOfLists( |
| absl::string_view str); |
| |
| // Returns the result of parsing the header value as a general List, if it can |
| // be parsed as one, or nullopt if it cannot. |
| // Structured-Headers Draft 15 only. |
| QUICHE_EXPORT std::optional<List> ParseList(absl::string_view str); |
| |
| // Returns the result of parsing the header value as a general Dictionary, if it |
| // can be parsed as one, or nullopt if it cannot. Structured-Headers Draft 15 |
| // only. |
| QUICHE_EXPORT std::optional<Dictionary> ParseDictionary(absl::string_view str); |
| |
| // Serialization is implemented for Structured-Headers Draft 15 only. |
| QUICHE_EXPORT std::optional<std::string> SerializeItem(const Item& value); |
| QUICHE_EXPORT std::optional<std::string> SerializeItem( |
| const ParameterizedItem& value); |
| QUICHE_EXPORT std::optional<std::string> SerializeList(const List& value); |
| QUICHE_EXPORT std::optional<std::string> SerializeDictionary( |
| const Dictionary& value); |
| |
| } // namespace structured_headers |
| } // namespace quiche |
| |
| #endif // QUICHE_COMMON_STRUCTURED_HEADERS_H_ |