urho3d/Source/Urho3D/Network/HttpRequest.cpp

//
// Copyright (c) 2008-2020 the Urho3D project.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
//

#include "../Precompiled.h"

#include "../Core/Profiler.h"
#include "../IO/Log.h"
#include "../Network/HttpRequest.h"

#ifdef __EMSCRIPTEN__
#include <emscripten.h>
#include <emscripten/bind.h>
#else
#include <Civetweb/civetweb.h>
#endif

#include "../DebugNew.h"

namespace Urho3D
{

static const unsigned ERROR_BUFFER_SIZE = 256;
static const unsigned READ_BUFFER_SIZE = 65536; // Must be a power of two

HttpRequest::HttpRequest(const String& url, const String& verb, const Vector<String>& headers, const String& postData) :
    url_(url.Trimmed()),
    verb_(!verb.Empty() ? verb : "GET"),
    headers_(headers),
    postData_(postData),
    state_(HTTP_INITIALIZING),
    httpReadBuffer_(new unsigned char[READ_BUFFER_SIZE]),
    readBuffer_(new unsigned char[READ_BUFFER_SIZE]),
    readPosition_(0),
    writePosition_(0)
{
    // Size of response is unknown, so just set maximum value. The position will also be changed
    // to maximum value once the request is done, signaling end for Deserializer::IsEof().
    size_ = M_MAX_UNSIGNED;

    URHO3D_LOGDEBUG("HTTP " + verb_ + " request to URL " + url_);

#ifdef URHO3D_SSL
    static bool sslInitialized = false;
    if (!sslInitialized)
    {
        mg_init_library(MG_FEATURES_TLS);
        sslInitialized = true;
    }
#endif

#if defined(__EMSCRIPTEN__)
    EM_ASM({
        let url = UTF8ToString($0);
        let handler = $1;
        fetch(url)
          .then(response => response.arrayBuffer())
          .then(data => {
              // Copy data to Emscripten heap (directly accessed from Module.HEAPU8)
              const nDataBytes = data.byteLength;
              const dataPtr = Module._malloc(nDataBytes);
              const dataHeap = new Uint8Array(Module.HEAPU8.buffer, dataPtr, nDataBytes);
              dataHeap.set(new Uint8Array(data));
              if (Module.JSResponse) {
                Module.JSResponse(handler, dataHeap.byteOffset, nDataBytes);
              } else {
                console.error('Module.JSResponse() methoddoes not exist');
              }
              Module._free(dataHeap.byteOffset);
          });
    }, url.CString(), this);
#elif defined(URHO3D_THREADING)
    // Start the worker thread to actually create the connection and read the response data.
    Run();
#else
    URHO3D_LOGERROR("HTTP request will not execute as threading is disabled");
#endif
}

#ifdef __EMSCRIPTEN__
void JSResponse(intptr_t requester, intptr_t data, int length)
{
    auto handler = reinterpret_cast<HttpRequest*>(requester);
    if (handler) {
        MutexLock lock(handler->mutex_);
        memcpy(handler->readBuffer_.Get(), reinterpret_cast<void*>(data), (size_t)length);
        handler->writePosition_ = length;
        handler->writePosition_ &= READ_BUFFER_SIZE - 1;
        handler->state_ = HTTP_CLOSED;
    }
}

using namespace emscripten;
EMSCRIPTEN_BINDINGS(HttpRequestHandler) {
    function("JSResponse", &JSResponse);
}
#endif

HttpRequest::~HttpRequest()
{
    Stop();
}

void HttpRequest::ThreadFunction()
{
    String protocol = "http";
    String host;
    String path = "/";
    int port = 80;

    unsigned protocolEnd = url_.Find("://");
    if (protocolEnd != String::NPOS)
    {
        protocol = url_.Substring(0, protocolEnd);
        host = url_.Substring(protocolEnd + 3);
    }
    else
        host = url_;

    unsigned pathStart = host.Find('/');
    if (pathStart != String::NPOS)
    {
        path = host.Substring(pathStart);
        host = host.Substring(0, pathStart);
    }

    unsigned portStart = host.Find(':');
    if (portStart != String::NPOS)
    {
        port = ToInt(host.Substring(portStart + 1));
        host = host.Substring(0, portStart);
    } else if (protocol.Compare("https", false) >= 0)
        port = 443;

    char errorBuffer[ERROR_BUFFER_SIZE];
    memset(errorBuffer, 0, sizeof(errorBuffer));

    String headersStr;
    for (unsigned i = 0; i < headers_.Size(); ++i)
    {
        // Trim and only add non-empty header strings
        String header = headers_[i].Trimmed();
        if (header.Length())
            headersStr += header + "\r\n";
    }

#ifndef __EMSCRIPTEN__
    // Initiate the connection. This may block due to DNS query
    mg_connection* connection = nullptr;

    if (postData_.Empty())
    {
        connection = mg_download(host.CString(), port, protocol.Compare("https", false) >= 0 ? 1 : 0, errorBuffer, sizeof(errorBuffer),
            "%s %s HTTP/1.0\r\n"
            "Host: %s\r\n"
            "%s"
            "\r\n", verb_.CString(), path.CString(), host.CString(), headersStr.CString());
    }
    else
    {
        connection = mg_download(host.CString(), port, protocol.Compare("https", false) >= 0 ? 1 : 0, errorBuffer, sizeof(errorBuffer),
            "%s %s HTTP/1.0\r\n"
            "Host: %s\r\n"
            "%s"
            "Content-Length: %d\r\n"
            "\r\n"
            "%s", verb_.CString(), path.CString(), host.CString(), headersStr.CString(), postData_.Length(), postData_.CString());
    }

    {
        MutexLock lock(mutex_);
        state_ = connection ? HTTP_OPEN : HTTP_ERROR;

        // If no connection could be made, store the error and exit
        if (state_ == HTTP_ERROR)
        {
            error_ = String(&errorBuffer[0]);
            return;
        }
    }

    // Loop while should run, read data from the connection, copy to the main thread buffer if there is space
    while (shouldRun_)
    {
        // Read less than full buffer to be able to distinguish between full and empty ring buffer. Reading may block
        int bytesRead = mg_read(connection, httpReadBuffer_.Get(), READ_BUFFER_SIZE / 4);
        if (bytesRead <= 0)
            break;

        mutex_.Acquire();

        // Wait until enough space in the main thread's ring buffer
        for (;;)
        {
            unsigned spaceInBuffer = READ_BUFFER_SIZE - ((writePosition_ - readPosition_) & (READ_BUFFER_SIZE - 1));
            if ((int)spaceInBuffer > bytesRead || !shouldRun_)
                break;

            mutex_.Release();
            Time::Sleep(5);
            mutex_.Acquire();
        }

        if (!shouldRun_)
        {
            mutex_.Release();
            break;
        }

        if (writePosition_ + bytesRead <= READ_BUFFER_SIZE)
            memcpy(readBuffer_.Get() + writePosition_, httpReadBuffer_.Get(), (size_t)bytesRead);
        else
        {
            // Handle ring buffer wrap
            unsigned part1 = READ_BUFFER_SIZE - writePosition_;
            unsigned part2 = bytesRead - part1;
            memcpy(readBuffer_.Get() + writePosition_, httpReadBuffer_.Get(), part1);
            memcpy(readBuffer_.Get(), httpReadBuffer_.Get() + part1, part2);
        }

        writePosition_ += bytesRead;
        writePosition_ &= READ_BUFFER_SIZE - 1;

        mutex_.Release();
    }

    // Close the connection
    mg_close_connection(connection);

#endif
    {
        MutexLock lock(mutex_);
        state_ = HTTP_CLOSED;
    }
}

unsigned HttpRequest::Read(void* dest, unsigned size)
{
#if defined(URHO3D_THREADING) || defined(__EMSCRIPTEN__)
    mutex_.Acquire();

    auto* destPtr = (unsigned char*)dest;
    unsigned sizeLeft = size;
    unsigned totalRead = 0;

    for (;;)
    {
        Pair<unsigned, bool> status{};

        for (;;)
        {
            status = CheckAvailableSizeAndEof();
            if (status.first_ || status.second_)
                break;
            // While no bytes and connection is still open, block until has some data
            mutex_.Release();
            Time::Sleep(5);
            mutex_.Acquire();
        }

        unsigned bytesAvailable = status.first_;

        if (bytesAvailable)
        {
            if (bytesAvailable > sizeLeft)
                bytesAvailable = sizeLeft;

            if (readPosition_ + bytesAvailable <= READ_BUFFER_SIZE)
                memcpy(destPtr, readBuffer_.Get() + readPosition_, bytesAvailable);
            else
            {
                // Handle ring buffer wrap
                unsigned part1 = READ_BUFFER_SIZE - readPosition_;
                unsigned part2 = bytesAvailable - part1;
                memcpy(destPtr, readBuffer_.Get() + readPosition_, part1);
                memcpy(destPtr + part1, readBuffer_.Get(), part2);
            }

            readPosition_ += bytesAvailable;
            readPosition_ &= READ_BUFFER_SIZE - 1;
            sizeLeft -= bytesAvailable;
            totalRead += bytesAvailable;
            destPtr += bytesAvailable;
        }

        if (!sizeLeft || !bytesAvailable)
            break;
    }

    mutex_.Release();
    return totalRead;
#else
    // Threading disabled, nothing to read
    return 0;
#endif
}

unsigned HttpRequest::Seek(unsigned position)
{
    return 0;
}

bool HttpRequest::IsEof() const
{
    MutexLock lock(mutex_);
    return CheckAvailableSizeAndEof().second_;
}

String HttpRequest::GetError() const
{
    MutexLock lock(mutex_);
    return error_;
}

HttpRequestState HttpRequest::GetState() const
{
    MutexLock lock(mutex_);
    return state_;
}

unsigned HttpRequest::GetAvailableSize() const
{
    MutexLock lock(mutex_);
    return CheckAvailableSizeAndEof().first_;
}

Pair<unsigned, bool> HttpRequest::CheckAvailableSizeAndEof() const
{
    unsigned size = (writePosition_ - readPosition_) & (READ_BUFFER_SIZE - 1);
    return {size, (state_ == HTTP_ERROR || (state_ == HTTP_CLOSED && !size))};
}

}