// Copyright (c) 2010 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.
// The rules for header parsing were borrowed from Firefox:
// http://lxr.mozilla.org/seamonkey/source/netwerk/protocol/http/src/nsHttpResponseHead.cpp
// The rules for parsing content-types were also borrowed from Firefox:
// http://lxr.mozilla.org/mozilla/source/netwerk/base/src/nsURLHelper.cpp#834
#include "net/http/http_response_headers.h"
#include <algorithm>
#include "base/logging.h"
#include "base/metrics/histogram.h"
#include "base/pickle.h"
#include "base/string_number_conversions.h"
#include "base/string_util.h"
#include "base/time.h"
#include "net/base/escape.h"
#include "net/http/http_util.h"
using base::Time;
using base::TimeDelta;
namespace net {
//-----------------------------------------------------------------------------
namespace {
// These headers are RFC 2616 hop-by-hop headers;
// not to be stored by caches.
const char* const kHopByHopResponseHeaders[] = {
"connection",
"proxy-connection",
"keep-alive",
"trailer",
"transfer-encoding",
"upgrade"
};
// These headers are challenge response headers;
// not to be stored by caches.
const char* const kChallengeResponseHeaders[] = {
"www-authenticate",
"proxy-authenticate"
};
// These headers are cookie setting headers;
// not to be stored by caches or disclosed otherwise.
const char* const kCookieResponseHeaders[] = {
"set-cookie",
"set-cookie2"
};
// These response headers are not copied from a 304/206 response to the cached
// response headers. This list is based on Mozilla's nsHttpResponseHead.cpp.
const char* const kNonUpdatedHeaders[] = {
"connection",
"proxy-connection",
"keep-alive",
"www-authenticate",
"proxy-authenticate",
"trailer",
"transfer-encoding",
"upgrade",
// these should never change:
"content-location",
"content-md5",
"etag",
// assume cache-control: no-transform
"content-encoding",
"content-range",
"content-type",
// some broken microsoft servers send 'content-length: 0' with 304s
"content-length"
};
bool ShouldUpdateHeader(const std::string::const_iterator& name_begin,
const std::string::const_iterator& name_end) {
for (size_t i = 0; i < arraysize(kNonUpdatedHeaders); ++i) {
if (LowerCaseEqualsASCII(name_begin, name_end, kNonUpdatedHeaders[i]))
return false;
}
return true;
}
// Functions for histogram initialization. The code 0 is put in the
// response map to track response codes that are invalid.
// TODO(gavinp): Greatly prune the collected codes once we learn which
// ones are not sent in practice, to reduce upload size & memory use.
enum {
HISTOGRAM_MIN_HTTP_RESPONSE_CODE = 100,
HISTOGRAM_MAX_HTTP_RESPONSE_CODE = 599,
};
std::vector<int> GetAllHttpResponseCodes() {
std::vector<int> codes;
codes.reserve(
HISTOGRAM_MAX_HTTP_RESPONSE_CODE - HISTOGRAM_MIN_HTTP_RESPONSE_CODE + 2);
codes.push_back(0);
for (int i = HISTOGRAM_MIN_HTTP_RESPONSE_CODE;
i <= HISTOGRAM_MAX_HTTP_RESPONSE_CODE; ++i)
codes.push_back(i);
return codes;
}
int MapHttpResponseCode(int code) {
if (HISTOGRAM_MIN_HTTP_RESPONSE_CODE <= code &&
code <= HISTOGRAM_MAX_HTTP_RESPONSE_CODE)
return code;
return 0;
}
} // namespace
struct HttpResponseHeaders::ParsedHeader {
// A header "continuation" contains only a subsequent value for the
// preceding header. (Header values are comma separated.)
bool is_continuation() const { return name_begin == name_end; }
std::string::const_iterator name_begin;
std::string::const_iterator name_end;
std::string::const_iterator value_begin;
std::string::const_iterator value_end;
};
//-----------------------------------------------------------------------------
HttpResponseHeaders::HttpResponseHeaders(const std::string& raw_input)
: response_code_(-1) {
Parse(raw_input);
// The most important thing to do with this histogram is find out
// the existence of unusual HTTP response codes. As it happens
// right now, there aren't double-constructions of response headers
// using this constructor, so our counts should also be accurate,
// without instantiating the histogram in two places. It is also
// important that this histogram not collect data in the other
// constructor, which rebuilds an histogram from a pickle, since
// that would actually create a double call between the original
// HttpResponseHeader that was serialized, and initialization of the
// new object from that pickle.
UMA_HISTOGRAM_CUSTOM_ENUMERATION("Net.HttpResponseCode",
MapHttpResponseCode(response_code_),
// Note the third argument is only
// evaluated once, see macro
// definition for details.
GetAllHttpResponseCodes());
}
HttpResponseHeaders::HttpResponseHeaders(const Pickle& pickle, void** iter)
: response_code_(-1) {
std::string raw_input;
if (pickle.ReadString(iter, &raw_input))
Parse(raw_input);
}
void HttpResponseHeaders::Persist(Pickle* pickle, PersistOptions options) {
if (options == PERSIST_RAW) {
pickle->WriteString(raw_headers_);
return; // Done.
}
HeaderSet filter_headers;
// Construct set of headers to filter out based on options.
if ((options & PERSIST_SANS_NON_CACHEABLE) == PERSIST_SANS_NON_CACHEABLE)
AddNonCacheableHeaders(&filter_headers);
if ((options & PERSIST_SANS_COOKIES) == PERSIST_SANS_COOKIES)
AddCookieHeaders(&filter_headers);
if ((options & PERSIST_SANS_CHALLENGES) == PERSIST_SANS_CHALLENGES)
AddChallengeHeaders(&filter_headers);
if ((options & PERSIST_SANS_HOP_BY_HOP) == PERSIST_SANS_HOP_BY_HOP)
AddHopByHopHeaders(&filter_headers);
if ((options & PERSIST_SANS_RANGES) == PERSIST_SANS_RANGES)
AddHopContentRangeHeaders(&filter_headers);
std::string blob;
blob.reserve(raw_headers_.size());
// This copies the status line w/ terminator null.
// Note raw_headers_ has embedded nulls instead of \n,
// so this just copies the first header line.
blob.assign(raw_headers_.c_str(), strlen(raw_headers_.c_str()) + 1);
for (size_t i = 0; i < parsed_.size(); ++i) {
DCHECK(!parsed_[i].is_continuation());
// Locate the start of the next header.
size_t k = i;
while (++k < parsed_.size() && parsed_[k].is_continuation()) {}
--k;
std::string header_name(parsed_[i].name_begin, parsed_[i].name_end);
StringToLowerASCII(&header_name);
if (filter_headers.find(header_name) == filter_headers.end()) {
// Make sure there is a null after the value.
blob.append(parsed_[i].name_begin, parsed_[k].value_end);
blob.push_back('\0');
}
i = k;
}
blob.push_back('\0');
pickle->WriteString(blob);
}
void HttpResponseHeaders::Update(const HttpResponseHeaders& new_headers) {
DCHECK(new_headers.response_code() == 304 ||
new_headers.response_code() == 206);
// Copy up to the null byte. This just copies the status line.
std::string new_raw_headers(raw_headers_.c_str());
new_raw_headers.push_back('\0');
HeaderSet updated_headers;
// NOTE: we write the new headers then the old headers for convenience. The
// order should not matter.
// Figure out which headers we want to take from new_headers:
for (size_t i = 0; i < new_headers.parsed_.size(); ++i) {
const HeaderList& new_parsed = new_headers.parsed_;
DCHECK(!new_parsed[i].is_continuation());
// Locate the start of the next header.
size_t k = i;
while (++k < new_parsed.size() && new_parsed[k].is_continuation()) {}
--k;
const std::string::const_iterator& name_begin = new_parsed[i].name_begin;
const std::string::const_iterator& name_end = new_parsed[i].name_end;
if (ShouldUpdateHeader(name_begin, name_end)) {
std::string name(name_begin, name_end);
StringToLowerASCII(&name);
updated_headers.insert(name);
// Preserve this header line in the merged result, making sure there is
// a null after the value.
new_raw_headers.append(name_begin, new_parsed[k].value_end);
new_raw_headers.push_back('\0');
}
i = k;
}
// Now, build the new raw headers.
MergeWithHeaders(new_raw_headers, updated_headers);
}
void HttpResponseHeaders::MergeWithHeaders(const std::string& raw_headers,
const HeaderSet& headers_to_remove) {
std::string new_raw_headers(raw_headers);
for (size_t i = 0; i < parsed_.size(); ++i) {
DCHECK(!parsed_[i].is_continuation());
// Locate the start of the next header.
size_t k = i;
while (++k < parsed_.size() && parsed_[k].is_continuation()) {}
--k;
std::string name(parsed_[i].name_begin, parsed_[i].name_end);
StringToLowerASCII(&name);
if (headers_to_remove.find(name) == headers_to_remove.end()) {
// It's ok to preserve this header in the final result.
new_raw_headers.append(parsed_[i].name_begin, parsed_[k].value_end);
new_raw_headers.push_back('\0');
}
i = k;
}
new_raw_headers.push_back('\0');
// Make this object hold the new data.
raw_headers_.clear();
parsed_.clear();
Parse(new_raw_headers);
}
void HttpResponseHeaders::RemoveHeader(const std::string& name) {
// Copy up to the null byte. This just copies the status line.
std::string new_raw_headers(raw_headers_.c_str());
new_raw_headers.push_back('\0');
std::string lowercase_name(name);
StringToLowerASCII(&lowercase_name);
HeaderSet to_remove;
to_remove.insert(lowercase_name);
MergeWithHeaders(new_raw_headers, to_remove);
}
void HttpResponseHeaders::AddHeader(const std::string& header) {
DCHECK_EQ('\0', raw_headers_[raw_headers_.size() - 2]);
DCHECK_EQ('\0', raw_headers_[raw_headers_.size() - 1]);
// Don't copy the last null.
std::string new_raw_headers(raw_headers_, 0, raw_headers_.size() - 1);
new_raw_headers.append(header);
new_raw_headers.push_back('\0');
new_raw_headers.push_back('\0');
// Make this object hold the new data.
raw_headers_.clear();
parsed_.clear();
Parse(new_raw_headers);
}
void HttpResponseHeaders::ReplaceStatusLine(const std::string& new_status) {
// Copy up to the null byte. This just copies the status line.
std::string new_raw_headers(new_status);
new_raw_headers.push_back('\0');
HeaderSet empty_to_remove;
MergeWithHeaders(new_raw_headers, empty_to_remove);
}
void HttpResponseHeaders::Parse(const std::string& raw_input) {
raw_headers_.reserve(raw_input.size());
// ParseStatusLine adds a normalized status line to raw_headers_
std::string::const_iterator line_begin = raw_input.begin();
std::string::const_iterator line_end =
find(line_begin, raw_input.end(), '\0');
// has_headers = true, if there is any data following the status line.
// Used by ParseStatusLine() to decide if a HTTP/0.9 is really a HTTP/1.0.
bool has_headers = (line_end != raw_input.end() &&
(line_end + 1) != raw_input.end() &&
*(line_end + 1) != '\0');
ParseStatusLine(line_begin, line_end, has_headers);
if (line_end == raw_input.end()) {
raw_headers_.push_back('\0');
return;
}
// Including a terminating null byte.
size_t status_line_len = raw_headers_.size();
// Now, we add the rest of the raw headers to raw_headers_, and begin parsing
// it (to populate our parsed_ vector).
raw_headers_.append(line_end + 1, raw_input.end());
// Adjust to point at the null byte following the status line
line_end = raw_headers_.begin() + status_line_len - 1;
HttpUtil::HeadersIterator headers(line_end + 1, raw_headers_.end(),
std::string(1, '\0'));
while (headers.GetNext()) {
AddHeader(headers.name_begin(),
headers.name_end(),
headers.values_begin(),
headers.values_end());
}
}
// Append all of our headers to the final output string.
void HttpResponseHeaders::GetNormalizedHeaders(std::string* output) const {
// copy up to the null byte. this just copies the status line.
output->assign(raw_headers_.c_str());
// headers may appear multiple times (not necessarily in succession) in the
// header data, so we build a map from header name to generated header lines.
// to preserve the order of the original headers, the actual values are kept
// in a separate list. finally, the list of headers is flattened to form
// the normalized block of headers.
//
// NOTE: We take special care to preserve the whitespace around any commas
// that may occur in the original response headers. Because our consumer may
// be a web app, we cannot be certain of the semantics of commas despite the
// fact that RFC 2616 says that they should be regarded as value separators.
//
typedef base::hash_map<std::string, size_t> HeadersMap;
HeadersMap headers_map;
HeadersMap::iterator iter = headers_map.end();
std::vector<std::string> headers;
for (size_t i = 0; i < parsed_.size(); ++i) {
DCHECK(!parsed_[i].is_continuation());
std::string name(parsed_[i].name_begin, parsed_[i].name_end);
std::string lower_name = StringToLowerASCII(name);
iter = headers_map.find(lower_name);
if (iter == headers_map.end()) {
iter = headers_map.insert(
HeadersMap::value_type(lower_name, headers.size())).first;
headers.push_back(name + ": ");
} else {
headers[iter->second].append(", ");
}
std::string::const_iterator value_begin = parsed_[i].value_begin;
std::string::const_iterator value_end = parsed_[i].value_end;
while (++i < parsed_.size() && parsed_[i].is_continuation())
value_end = parsed_[i].value_end;
--i;
headers[iter->second].append(value_begin, value_end);
}
for (size_t i = 0; i < headers.size(); ++i) {
output->push_back('\n');
output->append(headers[i]);
}
output->push_back('\n');
}
bool HttpResponseHeaders::GetNormalizedHeader(const std::string& name,
std::string* value) const {
// If you hit this assertion, please use EnumerateHeader instead!
DCHECK(!HttpUtil::IsNonCoalescingHeader(name));
value->clear();
bool found = false;
size_t i = 0;
while (i < parsed_.size()) {
i = FindHeader(i, name);
if (i == std::string::npos)
break;
found = true;
if (!value->empty())
value->append(", ");
std::string::const_iterator value_begin = parsed_[i].value_begin;
std::string::const_iterator value_end = parsed_[i].value_end;
while (++i < parsed_.size() && parsed_[i].is_continuation())
value_end = parsed_[i].value_end;
value->append(value_begin, value_end);
}
return found;
}
std::string HttpResponseHeaders::GetStatusLine() const {
// copy up to the null byte.
return std::string(raw_headers_.c_str());
}
std::string HttpResponseHeaders::GetStatusText() const {
// GetStatusLine() is already normalized, so it has the format:
// <http_version> SP <response_code> SP <status_text>
std::string status_text = GetStatusLine();
std::string::const_iterator begin = status_text.begin();
std::string::const_iterator end = status_text.end();
for (int i = 0; i < 2; ++i)
begin = find(begin, end, ' ') + 1;
return std::string(begin, end);
}
bool HttpResponseHeaders::EnumerateHeaderLines(void** iter,
std::string* name,
std::string* value) const {
size_t i = reinterpret_cast<size_t>(*iter);
if (i == parsed_.size())
return false;
DCHECK(!parsed_[i].is_continuation());
name->assign(parsed_[i].name_begin, parsed_[i].name_end);
std::string::const_iterator value_begin = parsed_[i].value_begin;
std::string::const_iterator value_end = parsed_[i].value_end;
while (++i < parsed_.size() && parsed_[i].is_continuation())
value_end = parsed_[i].value_end;
value->assign(value_begin, value_end);
*iter = reinterpret_cast<void*>(i);
return true;
}
bool HttpResponseHeaders::EnumerateHeader(void** iter, const std::string& name,
std::string* value) const {
size_t i;
if (!iter || !*iter) {
i = FindHeader(0, name);
} else {
i = reinterpret_cast<size_t>(*iter);
if (i >= parsed_.size()) {
i = std::string::npos;
} else if (!parsed_[i].is_continuation()) {
i = FindHeader(i, name);
}
}
if (i == std::string::npos) {
value->clear();
return false;
}
if (iter)
*iter = reinterpret_cast<void*>(i + 1);
value->assign(parsed_[i].value_begin, parsed_[i].value_end);
return true;
}
bool HttpResponseHeaders::HasHeaderValue(const std::string& name,
const std::string& value) const {
// The value has to be an exact match. This is important since
// 'cache-control: no-cache' != 'cache-control: no-cache="foo"'
void* iter = NULL;
std::string temp;
while (EnumerateHeader(&iter, name, &temp)) {
if (value.size() == temp.size() &&
std::equal(temp.begin(), temp.end(), value.begin(),
base::CaseInsensitiveCompare<char>()))
return true;
}
return false;
}
bool HttpResponseHeaders::HasHeader(const std::string& name) const {
return FindHeader(0, name) != std::string::npos;
}
HttpResponseHeaders::HttpResponseHeaders() : response_code_(-1) {
}
HttpResponseHeaders::~HttpResponseHeaders() {
}
// Note: this implementation implicitly assumes that line_end points at a valid
// sentinel character (such as '\0').
// static
HttpVersion HttpResponseHeaders::ParseVersion(
std::string::const_iterator line_begin,
std::string::const_iterator line_end) {
std::string::const_iterator p = line_begin;
// RFC2616 sec 3.1: HTTP-Version = "HTTP" "/" 1*DIGIT "." 1*DIGIT
// TODO: (1*DIGIT apparently means one or more digits, but we only handle 1).
// TODO: handle leading zeros, which is allowed by the rfc1616 sec 3.1.
if ((line_end - p < 4) || !LowerCaseEqualsASCII(p, p + 4, "http")) {
DVLOG(1) << "missing status line";
return HttpVersion();
}
p += 4;
if (p >= line_end || *p != '/') {
DVLOG(1) << "missing version";
return HttpVersion();
}
std::string::const_iterator dot = find(p, line_end, '.');
if (dot == line_end) {
DVLOG(1) << "malformed version";
return HttpVersion();
}
++p; // from / to first digit.
++dot; // from . to second digit.
if (!(*p >= '0' && *p <= '9' && *dot >= '0' && *dot <= '9')) {
DVLOG(1) << "malformed version number";
return HttpVersion();
}
uint16 major = *p - '0';
uint16 minor = *dot - '0';
return HttpVersion(major, minor);
}
// Note: this implementation implicitly assumes that line_end points at a valid
// sentinel character (such as '\0').
void HttpResponseHeaders::ParseStatusLine(
std::string::const_iterator line_begin,
std::string::const_iterator line_end,
bool has_headers) {
// Extract the version number
parsed_http_version_ = ParseVersion(line_begin, line_end);
// Clamp the version number to one of: {0.9, 1.0, 1.1}
if (parsed_http_version_ == HttpVersion(0, 9) && !has_headers) {
http_version_ = HttpVersion(0, 9);
raw_headers_ = "HTTP/0.9";
} else if (parsed_http_version_ >= HttpVersion(1, 1)) {
http_version_ = HttpVersion(1, 1);
raw_headers_ = "HTTP/1.1";
} else {
// Treat everything else like HTTP 1.0
http_version_ = HttpVersion(1, 0);
raw_headers_ = "HTTP/1.0";
}
if (parsed_http_version_ != http_version_) {
DVLOG(1) << "assuming HTTP/" << http_version_.major_value() << "."
<< http_version_.minor_value();
}
// TODO(eroman): this doesn't make sense if ParseVersion failed.
std::string::const_iterator p = find(line_begin, line_end, ' ');
if (p == line_end) {
DVLOG(1) << "missing response status; assuming 200 OK";
raw_headers_.append(" 200 OK");
raw_headers_.push_back('\0');
response_code_ = 200;
return;
}
// Skip whitespace.
while (*p == ' ')
++p;
std::string::const_iterator code = p;
while (*p >= '0' && *p <= '9')
++p;
if (p == code) {
DVLOG(1) << "missing response status number; assuming 200";
raw_headers_.append(" 200 OK");
response_code_ = 200;
return;
}
raw_headers_.push_back(' ');
raw_headers_.append(code, p);
raw_headers_.push_back(' ');
base::StringToInt(code, p, &response_code_);
// Skip whitespace.
while (*p == ' ')
++p;
// Trim trailing whitespace.
while (line_end > p && line_end[-1] == ' ')
--line_end;
if (p == line_end) {
DVLOG(1) << "missing response status text; assuming OK";
// Not super critical what we put here. Just use "OK"
// even if it isn't descriptive of response_code_.
raw_headers_.append("OK");
} else {
raw_headers_.append(p, line_end);
}
raw_headers_.push_back('\0');
}
size_t HttpResponseHeaders::FindHeader(size_t from,
const std::string& search) const {
for (size_t i = from; i < parsed_.size(); ++i) {
if (parsed_[i].is_continuation())
continue;
const std::string::const_iterator& name_begin = parsed_[i].name_begin;
const std::string::const_iterator& name_end = parsed_[i].name_end;
if (static_cast<size_t>(name_end - name_begin) == search.size() &&
std::equal(name_begin, name_end, search.begin(),
base::CaseInsensitiveCompare<char>()))
return i;
}
return std::string::npos;
}
void HttpResponseHeaders::AddHeader(std::string::const_iterator name_begin,
std::string::const_iterator name_end,
std::string::const_iterator values_begin,
std::string::const_iterator values_end) {
// If the header can be coalesced, then we should split it up.
if (values_begin == values_end ||
HttpUtil::IsNonCoalescingHeader(name_begin, name_end)) {
AddToParsed(name_begin, name_end, values_begin, values_end);
} else {
HttpUtil::ValuesIterator it(values_begin, values_end, ',');
while (it.GetNext()) {
AddToParsed(name_begin, name_end, it.value_begin(), it.value_end());
// clobber these so that subsequent values are treated as continuations
name_begin = name_end = raw_headers_.end();
}
}
}
void HttpResponseHeaders::AddToParsed(std::string::const_iterator name_begin,
std::string::const_iterator name_end,
std::string::const_iterator value_begin,
std::string::const_iterator value_end) {
ParsedHeader header;
header.name_begin = name_begin;
header.name_end = name_end;
header.value_begin = value_begin;
header.value_end = value_end;
parsed_.push_back(header);
}
void HttpResponseHeaders::AddNonCacheableHeaders(HeaderSet* result) const {
// Add server specified transients. Any 'cache-control: no-cache="foo,bar"'
// headers present in the response specify additional headers that we should
// not store in the cache.
const std::string kCacheControl = "cache-control";
const std::string kPrefix = "no-cache=\"";
std::string value;
void* iter = NULL;
while (EnumerateHeader(&iter, kCacheControl, &value)) {
if (value.size() > kPrefix.size() &&
value.compare(0, kPrefix.size(), kPrefix) == 0) {
// if it doesn't end with a quote, then treat as malformed
if (value[value.size()-1] != '\"')
continue;
// trim off leading and trailing bits
size_t len = value.size() - kPrefix.size() - 1;
TrimString(value.substr(kPrefix.size(), len), HTTP_LWS, &value);
size_t begin_pos = 0;
for (;;) {
// find the end of this header name
size_t comma_pos = value.find(',', begin_pos);
if (comma_pos == std::string::npos)
comma_pos = value.size();
size_t end = comma_pos;
while (end > begin_pos && strchr(HTTP_LWS, value[end - 1]))
end--;
// assuming the header is not emtpy, lowercase and insert into set
if (end > begin_pos) {
std::string name = value.substr(begin_pos, end - begin_pos);
StringToLowerASCII(&name);
result->insert(name);
}
// repeat
begin_pos = comma_pos + 1;
while (begin_pos < value.size() && strchr(HTTP_LWS, value[begin_pos]))
begin_pos++;
if (begin_pos >= value.size())
break;
}
}
}
}
void HttpResponseHeaders::AddHopByHopHeaders(HeaderSet* result) {
for (size_t i = 0; i < arraysize(kHopByHopResponseHeaders); ++i)
result->insert(std::string(kHopByHopResponseHeaders[i]));
}
void HttpResponseHeaders::AddCookieHeaders(HeaderSet* result) {
for (size_t i = 0; i < arraysize(kCookieResponseHeaders); ++i)
result->insert(std::string(kCookieResponseHeaders[i]));
}
void HttpResponseHeaders::AddChallengeHeaders(HeaderSet* result) {
for (size_t i = 0; i < arraysize(kChallengeResponseHeaders); ++i)
result->insert(std::string(kChallengeResponseHeaders[i]));
}
void HttpResponseHeaders::AddHopContentRangeHeaders(HeaderSet* result) {
result->insert("content-range");
}
void HttpResponseHeaders::GetMimeTypeAndCharset(std::string* mime_type,
std::string* charset) const {
mime_type->clear();
charset->clear();
std::string name = "content-type";
std::string value;
bool had_charset = false;
void* iter = NULL;
while (EnumerateHeader(&iter, name, &value))
HttpUtil::ParseContentType(value, mime_type, charset, &had_charset);
}
bool HttpResponseHeaders::GetMimeType(std::string* mime_type) const {
std::string unused;
GetMimeTypeAndCharset(mime_type, &unused);
return !mime_type->empty();
}
bool HttpResponseHeaders::GetCharset(std::string* charset) const {
std::string unused;
GetMimeTypeAndCharset(&unused, charset);
return !charset->empty();
}
bool HttpResponseHeaders::IsRedirect(std::string* location) const {
if (!IsRedirectResponseCode(response_code_))
return false;
// If we lack a Location header, then we can't treat this as a redirect.
// We assume that the first non-empty location value is the target URL that
// we want to follow. TODO(darin): Is this consistent with other browsers?
size_t i = std::string::npos;
do {
i = FindHeader(++i, "location");
if (i == std::string::npos)
return false;
// If the location value is empty, then it doesn't count.
} while (parsed_[i].value_begin == parsed_[i].value_end);
if (location) {
// Escape any non-ASCII characters to preserve them. The server should
// only be returning ASCII here, but for compat we need to do this.
*location = EscapeNonASCII(
std::string(parsed_[i].value_begin, parsed_[i].value_end));
}
return true;
}
// static
bool HttpResponseHeaders::IsRedirectResponseCode(int response_code) {
// Users probably want to see 300 (multiple choice) pages, so we don't count
// them as redirects that need to be followed.
return (response_code == 301 ||
response_code == 302 ||
response_code == 303 ||
response_code == 307);
}
// From RFC 2616 section 13.2.4:
//
// The calculation to determine if a response has expired is quite simple:
//
// response_is_fresh = (freshness_lifetime > current_age)
//
// Of course, there are other factors that can force a response to always be
// validated or re-fetched.
//
bool HttpResponseHeaders::RequiresValidation(const Time& request_time,
const Time& response_time,
const Time& current_time) const {
TimeDelta lifetime =
GetFreshnessLifetime(response_time);
if (lifetime == TimeDelta())
return true;
return lifetime <= GetCurrentAge(request_time, response_time, current_time);
}
// From RFC 2616 section 13.2.4:
//
// The max-age directive takes priority over Expires, so if max-age is present
// in a response, the calculation is simply:
//
// freshness_lifetime = max_age_value
//
// Otherwise, if Expires is present in the response, the calculation is:
//
// freshness_lifetime = expires_value - date_value
//
// Note that neither of these calculations is vulnerable to clock skew, since
// all of the information comes from the origin server.
//
// Also, if the response does have a Last-Modified time, the heuristic
// expiration value SHOULD be no more than some fraction of the interval since
// that time. A typical setting of this fraction might be 10%:
//
// freshness_lifetime = (date_value - last_modified_value) * 0.10
//
TimeDelta HttpResponseHeaders::GetFreshnessLifetime(
const Time& response_time) const {
// Check for headers that force a response to never be fresh. For backwards
// compat, we treat "Pragma: no-cache" as a synonym for "Cache-Control:
// no-cache" even though RFC 2616 does not specify it.
if (HasHeaderValue("cache-control", "no-cache") ||
HasHeaderValue("cache-control", "no-store") ||
HasHeaderValue("pragma", "no-cache") ||
HasHeaderValue("vary", "*")) // see RFC 2616 section 13.6
return TimeDelta(); // not fresh
// NOTE: "Cache-Control: max-age" overrides Expires, so we only check the
// Expires header after checking for max-age in GetFreshnessLifetime. This
// is important since "Expires: <date in the past>" means not fresh, but
// it should not trump a max-age value.
TimeDelta max_age_value;
if (GetMaxAgeValue(&max_age_value))
return max_age_value;
// If there is no Date header, then assume that the server response was
// generated at the time when we received the response.
Time date_value;
if (!GetDateValue(&date_value))
date_value = response_time;
Time expires_value;
if (GetExpiresValue(&expires_value)) {
// The expires value can be a date in the past!
if (expires_value > date_value)
return expires_value - date_value;
return TimeDelta(); // not fresh
}
// From RFC 2616 section 13.4:
//
// A response received with a status code of 200, 203, 206, 300, 301 or 410
// MAY be stored by a cache and used in reply to a subsequent request,
// subject to the expiration mechanism, unless a cache-control directive
// prohibits caching.
// ...
// A response received with any other status code (e.g. status codes 302
// and 307) MUST NOT be returned in a reply to a subsequent request unless
// there are cache-control directives or another header(s) that explicitly
// allow it.
//
// From RFC 2616 section 14.9.4:
//
// When the must-revalidate directive is present in a response received by
// a cache, that cache MUST NOT use the entry after it becomes stale to
// respond to a subsequent request without first revalidating it with the
// origin server. (I.e., the cache MUST do an end-to-end revalidation every
// time, if, based solely on the origin server's Expires or max-age value,
// the cached response is stale.)
//
if ((response_code_ == 200 || response_code_ == 203 ||
response_code_ == 206) &&
!HasHeaderValue("cache-control", "must-revalidate")) {
// TODO(darin): Implement a smarter heuristic.
Time last_modified_value;
if (GetLastModifiedValue(&last_modified_value)) {
// The last-modified value can be a date in the past!
if (last_modified_value <= date_value)
return (date_value - last_modified_value) / 10;
}
}
// These responses are implicitly fresh (unless otherwise overruled):
if (response_code_ == 300 || response_code_ == 301 || response_code_ == 410)
return TimeDelta::FromMicroseconds(kint64max);
return TimeDelta(); // not fresh
}
// From RFC 2616 section 13.2.3:
//
// Summary of age calculation algorithm, when a cache receives a response:
//
// /*
// * age_value
// * is the value of Age: header received by the cache with
// * this response.
// * date_value
// * is the value of the origin server's Date: header
// * request_time
// * is the (local) time when the cache made the request
// * that resulted in this cached response
// * response_time
// * is the (local) time when the cache received the
// * response
// * now
// * is the current (local) time
// */
// apparent_age = max(0, response_time - date_value);
// corrected_received_age = max(apparent_age, age_value);
// response_delay = response_time - request_time;
// corrected_initial_age = corrected_received_age + response_delay;
// resident_time = now - response_time;
// current_age = corrected_initial_age + resident_time;
//
TimeDelta HttpResponseHeaders::GetCurrentAge(const Time& request_time,
const Time& response_time,
const Time& current_time) const {
// If there is no Date header, then assume that the server response was
// generated at the time when we received the response.
Time date_value;
if (!GetDateValue(&date_value))
date_value = response_time;
// If there is no Age header, then assume age is zero. GetAgeValue does not
// modify its out param if the value does not exist.
TimeDelta age_value;
GetAgeValue(&age_value);
TimeDelta apparent_age = std::max(TimeDelta(), response_time - date_value);
TimeDelta corrected_received_age = std::max(apparent_age, age_value);
TimeDelta response_delay = response_time - request_time;
TimeDelta corrected_initial_age = corrected_received_age + response_delay;
TimeDelta resident_time = current_time - response_time;
TimeDelta current_age = corrected_initial_age + resident_time;
return current_age;
}
bool HttpResponseHeaders::GetMaxAgeValue(TimeDelta* result) const {
std::string name = "cache-control";
std::string value;
const char kMaxAgePrefix[] = "max-age=";
const size_t kMaxAgePrefixLen = arraysize(kMaxAgePrefix) - 1;
void* iter = NULL;
while (EnumerateHeader(&iter, name, &value)) {
if (value.size() > kMaxAgePrefixLen) {
if (LowerCaseEqualsASCII(value.begin(),
value.begin() + kMaxAgePrefixLen,
kMaxAgePrefix)) {
int64 seconds;
base::StringToInt64(value.begin() + kMaxAgePrefixLen,
value.end(),
&seconds);
*result = TimeDelta::FromSeconds(seconds);
return true;
}
}
}
return false;
}
bool HttpResponseHeaders::GetAgeValue(TimeDelta* result) const {
std::string value;
if (!EnumerateHeader(NULL, "Age", &value))
return false;
int64 seconds;
base::StringToInt64(value, &seconds);
*result = TimeDelta::FromSeconds(seconds);
return true;
}
bool HttpResponseHeaders::GetDateValue(Time* result) const {
return GetTimeValuedHeader("Date", result);
}
bool HttpResponseHeaders::GetLastModifiedValue(Time* result) const {
return GetTimeValuedHeader("Last-Modified", result);
}
bool HttpResponseHeaders::GetExpiresValue(Time* result) const {
return GetTimeValuedHeader("Expires", result);
}
bool HttpResponseHeaders::GetTimeValuedHeader(const std::string& name,
Time* result) const {
std::string value;
if (!EnumerateHeader(NULL, name, &value))
return false;
std::wstring value_wide(value.begin(), value.end()); // inflate ascii
return Time::FromString(value_wide.c_str(), result);
}
bool HttpResponseHeaders::IsKeepAlive() const {
if (http_version_ < HttpVersion(1, 0))
return false;
// NOTE: It is perhaps risky to assume that a Proxy-Connection header is
// meaningful when we don't know that this response was from a proxy, but
// Mozilla also does this, so we'll do the same.
std::string connection_val;
if (!EnumerateHeader(NULL, "connection", &connection_val))
EnumerateHeader(NULL, "proxy-connection", &connection_val);
bool keep_alive;
if (http_version_ == HttpVersion(1, 0)) {
// HTTP/1.0 responses default to NOT keep-alive
keep_alive = LowerCaseEqualsASCII(connection_val, "keep-alive");
} else {
// HTTP/1.1 responses default to keep-alive
keep_alive = !LowerCaseEqualsASCII(connection_val, "close");
}
return keep_alive;
}
bool HttpResponseHeaders::HasStrongValidators() const {
std::string etag_value;
EnumerateHeader(NULL, "etag", &etag_value);
if (!etag_value.empty()) {
size_t slash = etag_value.find('/');
if (slash == std::string::npos || slash == 0)
return true;
std::string::const_iterator i = etag_value.begin();
std::string::const_iterator j = etag_value.begin() + slash;
HttpUtil::TrimLWS(&i, &j);
if (!LowerCaseEqualsASCII(i, j, "w"))
return true;
}
Time last_modified;
if (!GetLastModifiedValue(&last_modified))
return false;
Time date;
if (!GetDateValue(&date))
return false;
return ((date - last_modified).InSeconds() >= 60);
}
// From RFC 2616:
// Content-Length = "Content-Length" ":" 1*DIGIT
int64 HttpResponseHeaders::GetContentLength() const {
void* iter = NULL;
std::string content_length_val;
if (!EnumerateHeader(&iter, "content-length", &content_length_val))
return -1;
if (content_length_val.empty())
return -1;
if (content_length_val[0] == '+')
return -1;
int64 result;
bool ok = base::StringToInt64(content_length_val, &result);
if (!ok || result < 0)
return -1;
return result;
}
// From RFC 2616 14.16:
// content-range-spec =
// bytes-unit SP byte-range-resp-spec "/" ( instance-length | "*" )
// byte-range-resp-spec = (first-byte-pos "-" last-byte-pos) | "*"
// instance-length = 1*DIGIT
// bytes-unit = "bytes"
bool HttpResponseHeaders::GetContentRange(int64* first_byte_position,
int64* last_byte_position,
int64* instance_length) const {
void* iter = NULL;
std::string content_range_spec;
*first_byte_position = *last_byte_position = *instance_length = -1;
if (!EnumerateHeader(&iter, "content-range", &content_range_spec))
return false;
// If the header value is empty, we have an invalid header.
if (content_range_spec.empty())
return false;
size_t space_position = content_range_spec.find(' ');
if (space_position == std::string::npos)
return false;
// Invalid header if it doesn't contain "bytes-unit".
std::string::const_iterator content_range_spec_begin =
content_range_spec.begin();
std::string::const_iterator content_range_spec_end =
content_range_spec.begin() + space_position;
HttpUtil::TrimLWS(&content_range_spec_begin, &content_range_spec_end);
if (!LowerCaseEqualsASCII(content_range_spec_begin,
content_range_spec_end,
"bytes")) {
return false;
}
size_t slash_position = content_range_spec.find('/', space_position + 1);
if (slash_position == std::string::npos)
return false;
// Obtain the part behind the space and before slash.
std::string::const_iterator byte_range_resp_spec_begin =
content_range_spec.begin() + space_position + 1;
std::string::const_iterator byte_range_resp_spec_end =
content_range_spec.begin() + slash_position;
HttpUtil::TrimLWS(&byte_range_resp_spec_begin, &byte_range_resp_spec_end);
// Parse the byte-range-resp-spec part.
std::string byte_range_resp_spec(byte_range_resp_spec_begin,
byte_range_resp_spec_end);
// If byte-range-resp-spec != "*".
if (!LowerCaseEqualsASCII(byte_range_resp_spec, "*")) {
size_t minus_position = byte_range_resp_spec.find('-');
if (minus_position != std::string::npos) {
// Obtain first-byte-pos.
std::string::const_iterator first_byte_pos_begin =
byte_range_resp_spec.begin();
std::string::const_iterator first_byte_pos_end =
byte_range_resp_spec.begin() + minus_position;
HttpUtil::TrimLWS(&first_byte_pos_begin, &first_byte_pos_end);
bool ok = base::StringToInt64(first_byte_pos_begin,
first_byte_pos_end,
first_byte_position);
// Obtain last-byte-pos.
std::string::const_iterator last_byte_pos_begin =
byte_range_resp_spec.begin() + minus_position + 1;
std::string::const_iterator last_byte_pos_end =
byte_range_resp_spec.end();
HttpUtil::TrimLWS(&last_byte_pos_begin, &last_byte_pos_end);
ok &= base::StringToInt64(last_byte_pos_begin,
last_byte_pos_end,
last_byte_position);
if (!ok) {
*first_byte_position = *last_byte_position = -1;
return false;
}
if (*first_byte_position < 0 || *last_byte_position < 0 ||
*first_byte_position > *last_byte_position)
return false;
} else {
return false;
}
}
// Parse the instance-length part.
// If instance-length == "*".
std::string::const_iterator instance_length_begin =
content_range_spec.begin() + slash_position + 1;
std::string::const_iterator instance_length_end =
content_range_spec.end();
HttpUtil::TrimLWS(&instance_length_begin, &instance_length_end);
if (LowerCaseEqualsASCII(instance_length_begin, instance_length_end, "*")) {
return false;
} else if (!base::StringToInt64(instance_length_begin,
instance_length_end,
instance_length)) {
*instance_length = -1;
return false;
}
// We have all the values; let's verify that they make sense for a 206
// response.
if (*first_byte_position < 0 || *last_byte_position < 0 ||
*instance_length < 0 || *instance_length - 1 < *last_byte_position)
return false;
return true;
}
} // namespace net