httpclient.cc

本人收集整理的一份c/c++跨平台网络库

    return HE_CACHE;
  }

  // Write all unknown and end-to-end headers to a cache file
  for (HttpData::const_iterator it = response_.begin();
       it != response_.end(); ++it) {
    HttpHeader header;
    if (FromString(header, it->first) && !HttpHeaderIsEndToEnd(header))
      continue;
    std::string formatted_header(it->first);
    formatted_header.append(": ");
    formatted_header.append(it->second);
    formatted_header.append("\r\n");
    StreamResult result = stream->WriteAll(formatted_header.data(),
                                           formatted_header.length(),
                                           NULL, NULL);
    if (SR_SUCCESS != result) {
      LOG_F(LS_ERROR) << "Couldn't write header cache";
      return HE_CACHE;
    }
  }

  return HE_NONE;
}

void HttpClient::CompleteCacheFile() {
  // Restore previous response document
  StreamTap* tap = static_cast<StreamTap*>(response_.document.release());
  response_.document.reset(tap->Detach());

  int error;
  StreamResult result = tap->GetTapResult(&error);

  // Delete the tap and cache stream (which completes cache unlock)
  delete tap;

  if (SR_SUCCESS != result) {
    LOG(LS_ERROR) << "Cache file error: " << error;
    cache_->DeleteResource(GetCacheID(server_, request_));
  }
}

bool HttpClient::CheckCache() {
  ASSERT(NULL != cache_);
  ASSERT(CS_READY == cache_state_);

  std::string id = GetCacheID(server_, request_);
  if (!cache_->HasResource(id)) {
    // No cache file available
    return false;
  }

  HttpError error = ReadCacheHeaders(id, true);

  if (HE_NONE == error) {
    switch (HttpGetCacheState(request_, response_)) {
    case HCS_FRESH:
      // Cache content is good, read from cache
      break;
    case HCS_STALE:
      // Cache content may be acceptable.  Issue a validation request.
      if (PrepareValidate()) {
        return false;
      }
      // Couldn't validate, fall through.
    case HCS_NONE:
      // Cache content is not useable.  Issue a regular request.
      response_.clear(false);
      return false;
    }
  }

  if (HE_NONE == error) {
    error = ReadCacheBody(id);
    cache_state_ = CS_READY;
  }

  if (HE_CACHE == error) {
    LOG_F(LS_WARNING) << "Cache failure, continuing with normal request";
    response_.clear(false);
    return false;
  }

  SignalHttpClientComplete(this, error);
  return true;
}

HttpError HttpClient::ReadCacheHeaders(const std::string& id, bool override) {
  scoped_ptr<StreamInterface> stream(cache_->ReadResource(id, kCacheHeader));
  if (!stream.get()) {
    return HE_CACHE;
  }

  HttpData::HeaderCombine combine =
    override ? HttpData::HC_REPLACE : HttpData::HC_AUTO;

  while (true) {
    std::string formatted_header;
    StreamResult result = stream->ReadLine(&formatted_header);
    if (SR_EOS == result)
      break;

    if (SR_SUCCESS != result) {
      LOG_F(LS_ERROR) << "ReadLine error in cache headers";
      return HE_CACHE;
    }
    size_t end_of_name = formatted_header.find(':');
    if (std::string::npos == end_of_name) {
      LOG_F(LS_WARNING) << "Malformed cache header";
      continue;
    }
    size_t start_of_value = end_of_name + 1;
    size_t end_of_value = formatted_header.length();
    while ((start_of_value < end_of_value)
           && isspace(formatted_header[start_of_value]))
      ++start_of_value;
    while ((start_of_value < end_of_value)
           && isspace(formatted_header[end_of_value-1]))
     --end_of_value;
    size_t value_length = end_of_value - start_of_value;

    std::string name(formatted_header.substr(0, end_of_name));
    std::string value(formatted_header.substr(start_of_value, value_length));
    response_.changeHeader(name, value, combine);
  }

  response_.scode = HC_OK;
  return HE_NONE;
}

HttpError HttpClient::ReadCacheBody(const std::string& id) {
  cache_state_ = CS_READING;

  HttpError error = HE_NONE;

  size_t data_size;
  scoped_ptr<StreamInterface> stream(cache_->ReadResource(id, kCacheBody));
  if (!stream.get() || !stream->GetSize(&data_size)) {
    LOG_F(LS_ERROR) << "Unavailable cache body";
    error = HE_CACHE;
  } else {
    error = OnHeaderAvailable(false, false, data_size);
  }

  if ((HE_NONE == error)
      && (HV_HEAD != request_.verb)
      && (NULL != response_.document.get())) {
    char buffer[1024 * 64];
    StreamResult result = Flow(stream.get(), buffer, ARRAY_SIZE(buffer),
                               response_.document.get());
    if (SR_SUCCESS != result) {
      error = HE_STREAM;
    }
  }

  return error;
}

bool HttpClient::PrepareValidate() {
  ASSERT(CS_READY == cache_state_);
  // At this point, request_ contains the pending request, and response_
  // contains the cached response headers.  Reformat the request to validate
  // the cached content.
  HttpValidatorStrength vs_required = HttpRequestValidatorLevel(request_);
  HttpValidatorStrength vs_available = HttpResponseValidatorLevel(response_);
  if (vs_available < vs_required) {
    return false;
  }
  std::string value;
  if (response_.hasHeader(HH_ETAG, &value)) {
    request_.addHeader(HH_IF_NONE_MATCH, value);
  }
  if (response_.hasHeader(HH_LAST_MODIFIED, &value)) {
    request_.addHeader(HH_IF_MODIFIED_SINCE, value);
  }
  response_.clear(false);
  cache_state_ = CS_VALIDATING;
  return true;
}

HttpError HttpClient::CompleteValidate() {
  ASSERT(CS_VALIDATING == cache_state_);

  std::string id = GetCacheID(server_, request_);

  // Merge cached headers with new headers
  HttpError error = ReadCacheHeaders(id, false);
  if (HE_NONE != error) {
    // Rewrite merged headers to cache
    CacheLock lock(cache_, id);
    error = WriteCacheHeaders(id);
  }
  if (HE_NONE != error) {
    error = ReadCacheBody(id);
  }
  return error;
}

HttpError HttpClient::OnHeaderAvailable(bool ignore_data, bool chunked,
                                        size_t data_size) {
  if (!ignore_data && !chunked && response_.document.get()) {
    // Attempt to pre-allocate space for the downloaded data.
    if (!response_.document->ReserveSize(data_size)) {
      return HE_OVERFLOW;
    }
  }
  SignalHeaderAvailable(this, chunked, data_size);
  return HE_NONE;
}

//
// HttpBase Implementation
//

HttpError HttpClient::onHttpHeaderComplete(bool chunked, size_t& data_size) {
  if (CS_VALIDATING == cache_state_) {
    if (HC_NOT_MODIFIED == response_.scode) {
      return CompleteValidate();
    }
    // Should we remove conditional headers from request?
    cache_state_ = CS_READY;
    cache_->DeleteResource(GetCacheID(server_, request_));
    // Continue processing response as normal
  }

  ASSERT(!IsCacheActive());
  if ((request_.verb == HV_HEAD) || !HttpCodeHasBody(response_.scode)) {
    // HEAD requests and certain response codes contain no body
    data_size = 0;
  }
  if ((HttpCodeIsRedirection(response_.scode) && !fail_redirect_)
      || ((HC_PROXY_AUTHENTICATION_REQUIRED == response_.scode)
          && (PROXY_HTTPS == proxy_.type))) {
    // We're going to issue another request, so ignore the incoming data.
    base_.set_ignore_data(true);
  }

  HttpError error = OnHeaderAvailable(base_.ignore_data(), chunked, data_size);
  if (HE_NONE != error) {
    return error;
  }

  if ((NULL != cache_)
      && !base_.ignore_data()
      && HttpShouldCache(request_, response_)) {
    if (BeginCacheFile()) {
      cache_state_ = CS_WRITING;
    }
  }
  return HE_NONE;
}

void HttpClient::onHttpComplete(HttpMode mode, HttpError err) {
  if (err != HE_NONE) {
    // fall through
  } else if (mode == HM_CONNECT) {
    base_.send(&request_);
    return;
  } else if ((mode == HM_SEND) || HttpCodeIsInformational(response_.scode)) {
    // If you're interested in informational headers, catch
    // SignalHeaderAvailable.
    base_.recv(&response_);
    return;
  } else {
    if (!HttpShouldKeepAlive(response_)) {
      LOG(INFO) << "HttpClient: closing socket";
      base_.stream()->Close();
    }
    if (HttpCodeIsRedirection(response_.scode) && !fail_redirect_) {
      std::string value;
      if (!response_.hasHeader(HH_LOCATION, &value)) {
        err = HE_PROTOCOL;
      } else {
        Url<char> purl(value);
        set_server(SocketAddress(purl.server(), purl.port(), false));
        request_.path = purl.full_path();
        if (response_.scode == HC_SEE_OTHER) {
          request_.verb = HV_GET;
          request_.clearHeader(HH_CONTENT_TYPE);
          request_.clearHeader(HH_CONTENT_LENGTH);
          request_.document.reset();
        } else if (request_.document.get() && !request_.document->Rewind()) {
          // Unable to replay the request document.
          err = HE_STREAM;
        }
      }
      if (err == HE_NONE) {
        context_.reset();
        response_.clear(false);
        release();
        start();
        return;
      }
    } else if ((HC_PROXY_AUTHENTICATION_REQUIRED == response_.scode)
               && (PROXY_HTTPS == proxy_.type)) {
      std::string response, auth_method;
      HttpData::const_iterator begin = response_.begin(HH_PROXY_AUTHENTICATE);
      HttpData::const_iterator end = response_.end(HH_PROXY_AUTHENTICATE);
      for (HttpData::const_iterator it = begin; it != end; ++it) {
        HttpAuthResult res = HttpAuthenticate(
          it->second.data(), it->second.size(),
          proxy_.address,
          ToString(request_.verb), request_.path,
          proxy_.username, proxy_.password,
          *context_.use(), response, auth_method);
        if (res == HAR_RESPONSE) {
          request_.setHeader(HH_PROXY_AUTHORIZATION, response);
          if (request_.document.get() && !request_.document->Rewind()) {
            err = HE_STREAM;
          } else {
            // Explicitly do not reset the HttpAuthContext
            response_.clear(false);
            // TODO: Reuse socket when authenticating?
            release();
            start();
            return;
          }
        } else if (res == HAR_IGNORE) {
          LOG(INFO) << "Ignoring Proxy-Authenticate: " << auth_method;
          continue;
        } else {
          break;
        }
      }
    }
  }
  if (CS_WRITING == cache_state_) {
    CompleteCacheFile();
    cache_state_ = CS_READY;
  } else if (CS_READING == cache_state_) {
    cache_state_ = CS_READY;
  }
  release();
  SignalHttpClientComplete(this, err);
}

void HttpClient::onHttpClosed(HttpError err) {
  SignalHttpClientClosed(this, err);
}

//////////////////////////////////////////////////////////////////////

} // namespace talk_base