Boost Asio 和 Beast mulitpart/form-data 从 streambuf 保存二进制文件
Boost Asio and Beast mulitpart/form-data save binary from streambuf
我的结果看起来像...
POST /post HTTP/1.1
Host: localhost:3003
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:62.0)
Gecko/20100101 Firefox/62.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://localhost:3003/profile
Content-type: multipart/form-data
Content-Length: 14708
Cookie: mycookie=7bdbed41954cd4133a172acb92988e58
Connection: keep-alive
-----------------------------4636945214860352321751082034
...
binary characters...
...
-----------------------------4636945214860352321751082034
购自
boost::asio::async_read(
socket_,
strmbuffer_,
boost::asio::transfer_exactly(bytes_to_transfer),
strand_.wrap(
[this, self](boost::system::error_code ec, std::size_t bytes_transferred)
{
std::stringstream ss;
ss << buffer_data; // from socket_.async_read_some()
ss << &strmbuffer_; // now stringstream contains everything
// the character routine which writes the above
// and which i use for output...
std::string output_file = "../../upload/test.png";
std::ofstream outfile(output_file);
char c;
unsigned bl = boundary.length();
bool endfile = false;
unsigned bufsize = 512;
if(outfile){
char buffer[bufsize];
while(!endfile){
// here looks like below
// to find and pass the first boundary
} // then stream continues...
while(!endfile){
unsigned j = 0;
unsigned k;
memset(buffer, 0, bufsize); // redundant
while(j < bufsize && ss.get(c) && !endfile){
buffer[j] = c;
k = 0;
while(boundary[bl - 1 - k] == buffer[j - k]){
if(k >= bl - 1){
endfile = true;
break;
}
k++;
}
j++;
}
outfile.write(buffer, j);
j = 0;
}
}
}
);
...本质上。因此，接收
socket_.async_read_some()
给我一个
boost::array<char, 8192> buffer_;
这给了我 http 请求信息。但是在multipart/form-data的情况下，它读过了第一个边界，这意味着下一个read()看不到它。啊！ （async_read_until() 也是如此。）因此，在
boost::asio::async_read()
我转换
boost::asio::streambuf strmbuffer_;
到字符串流并将它们加在一起以获得上面的 std::cout 结果。
我根本不相信我应该使用 stringstream。但是上面的例程（使用 stringstream）在 Boost::Beast 中运行良好。它不在 Asio 中。不幸的是，在 Beast 中接收 http 请求的 string_body 类型有大小限制，我相信是 1 兆。不知道如何更改它。
我在任何地方都找不到关于这个主题的信息。或许，情报太危险了。如果他们告诉我，他们就得杀了我。我应该在 Asio 中使用什么将二进制数据写入磁盘？
默认情况下，HTTP 请求解析器以 1 兆字节的限制开始。这是为了防止客户端发送非常大或无穷无尽的 body 数据的资源耗尽攻击。您可以通过使用所需的最大值调用 parser::body_limit 来轻松更改此限制。这在文档中有描述：
https://www.boost.org/doc/libs/1_68_0/libs/beast/doc/html/beast/ref/boost__beast__http__parser/body_limit.html
https://www.boost.org/doc/libs/1_68_0/libs/beast/doc/html/beast/using_http/buffer_oriented_parsing.html
为了调整解析器参数，例如 body 限制（或 header 限制），您需要使用 "parser stream operation" 界面。这在这里解释：
我会 post 我自己的部分解决方案。它在 14.2kb png 上没有错误。高于此值可能会导致段错误，除非调整 'magic' 数字，如下所示。
我正在使用 Boost Asio HTTP 服务器示例 C++11。
在connection.hpp中，更改...
//boost::array<char, 8192> buffer_;
boost::array<char, 512> buffer_;
此外，添加...
boost::asio::streambuf strmbuffer_;
在connection.cpp中，这里是connection::handle_read()...
void connection::handle_read(const boost::system::error_code& e, std::size_t bytes_transferred)
{
if (!e)
{
//*** buffer_.data() for this file ***
//
//POST /post HTTP/1.1
//Host: localhost:3003
//User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0
//Accept: */*
//Accept-Language: en-US,en;q=0.5
//Accept-Encoding: gzip, deflate
//Referer: http://localhost:3003/profile
//Content-type: multipart/form-data
//Content-Length: 14710
//Cookie: knowstoryadmin=7bdbed41954cd4133a172acb92988e58
//Connection: keep-alive
//
//-----------------------------14071968205478138611648202646
//Content-Disposition: form-data; name="admin_profile_image_load"; filename="tlc-logo.png"
//Content-Type: image/png
//
//�PNG
//▒
std::stringstream strm1;
std::string buffer_data = buffer_.data();
strm1 << buffer_data;
std::string method;
std::smatch match_method;
std::regex regex_method ("\b([^ ]*)( )([^ ]*)( HTTP/1.1)([^ ]*)");
std::string content_type;
std::smatch match_content_type;
std::regex regex_content_type ("\b(Content-type: )([^ ]*)");
std::string line;
while (std::getline(strm1, line)) {
if (std::regex_search(line, match_method, regex_method)) {
method = match_method[0];
method = method.substr(0, method.find(' '));
boost::trim(method);
//std::cout << method << std::endl;
}
if (std::regex_search(line, match_content_type, regex_content_type)) {
content_type = match_content_type[0];
boost::erase_all(content_type, "Content-type:");
boost::trim(content_type);
//std::cout << content_type << std::endl;
}
}
if (method == "POST") {
if (content_type == "multipart/form-data") {
std::string content_length;
std::smatch match_content_length;
std::regex regex_content_length ("\b(Content-Length: )([^ ]*)");
std::string filename;
std::smatch match_filename;
std::regex regex_filename ("\b(filename)([^ ]*)");
std::string action;
std::smatch match_action;
std::regex regex_action ("\b(name)([^ ]*)");
std::string boundary;
std::smatch match_boundary;
std::regex regex_boundary ("([-]{10,}[0-9]{10,})");
std::string line;
strm1.clear();
strm1 << buffer_data;
while (std::getline(strm1, line)) {
if (std::regex_search(line, match_content_length, regex_content_length)) {
//Content-Length: 14710
content_length = match_content_length[0];
boost::erase_all(content_length, "Content-Length:");
boost::trim(content_length);
//std::cout << content_length << std::endl;
}
if (std::regex_search(line, match_filename, regex_filename)) {
filename = match_filename[0];
boost::erase_all(filename, "\"");
boost::erase_all(action, ";");
boost::erase_all(filename, "filename=");
std::size_t found = filename.find_last_of(".");
std::size_t len = filename.length();
std::string mime = filename.substr(found, len);
boost::trim(filename);
//std::cout << filename << std::endl;
//std::cout << mime << std::endl;
}
if (std::regex_search(line, match_action, regex_action)) {
action = match_action[0];
boost::erase_all(action, "\"");
boost::erase_all(action, ";");
boost::erase_all(action, "name=");
boost::trim(action);
//std::cout << action << std::endl;
}
if (std::regex_search(line, match_boundary, regex_boundary)) {
boundary = match_boundary[0];
boost::trim(boundary);
//std::cout << boundary << std::endl;
}
}
//pubseekpos works as expected, but useless here
//strmbuffer_.pubseekpos(bytes_transferred);
//content length minus bytes_transfered does NOT yield
//the right result. The number, 392, is the 'magic' number
//adjustment for this file size, approx 14.2kb, that i found
//by trial and error.
//Adjusting the magic number is necessary for every image size
//in order to avoid a segfault.
//bytes_transferred, for each read(), is the only 'reliable'
//number with which to work, as far as i know.
//If there is a brainier way of calculating this,
//i don't care, anymore.
int n_content_length = std::stoi(content_length);
int transfer = n_content_length - bytes_transferred + 392;
auto self(shared_from_this());
boost::asio::async_read(
socket_,
strmbuffer_,
boost::asio::transfer_exactly(transfer),
strand_.wrap(
[this, self, boundary](boost::system::error_code ec, std::size_t bytes_transferred)
{
std::stringstream strm2;
strm2 << &strmbuffer_;
std::string line;
unsigned bufsize = 512;
while (std::getline(strm2, line))
{
if(line.length() == 1){
std::string output_file = "../../upload/test.png";
std::ofstream outfile(output_file);
char c;
unsigned bl = boundary.length();
bool endfile = false;
if(outfile){
char buffer[bufsize];
while(!endfile){
unsigned j = 0;
unsigned k;
while(j < bufsize && strm2.get(c) && !endfile){
buffer[j] = c;
k = 0;
while(boundary[bl - 1 - k] == buffer[j - k]){
if(k >= bl - 1){
endfile = true;
break;
}
k++;
}
j++;
}
outfile.write(buffer, j);
j = 0;
};
outfile.close();
std::cout << "outfile close" << std::endl;
break;
}
}
}
}
)
);
}
else {
// POST AJAX
std::cout << "connection " << method << std::endl;
}
}
else {
boost::tribool result;
boost::tie(result, boost::tuples::ignore) = request_parser_.parse(
request_, buffer_.data(), buffer_.data() + bytes_transferred);
if (result)
{
request_handler_.handle_request(
request_,
reply_);
boost::asio::async_write(
socket_,
reply_.to_buffers(),
strand_.wrap(
boost::bind(
&connection::handle_write,
shared_from_this(),
boost::asio::placeholders::error)
));
}
else if (!result)
{
reply_ = reply::stock_reply(reply::bad_request);
boost::asio::async_write(
socket_,
reply_.to_buffers(),
strand_.wrap(
boost::bind(&connection::handle_write, shared_from_this(),
boost::asio::placeholders::error)));
}
else
{
socket_.async_read_some(
boost::asio::buffer(buffer_),
strand_.wrap(
boost::bind(
&connection::handle_read,
shared_from_this(),
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred)));
}
}
}
}
对于这个 Asio 示例，此部分解决方案相当 'unobtrusive'。 request_handler class 不变，服务于 GET。
在connection::start()中，我尝试了async_read。但结果更难以预测。这意味着我必须附加两个字符串，一个由 strmbuffer1_ 制成，另一个由 strmbuffer2_ 制成，以便在文件输出循环中一起构造（破解）流。无论我在 cout<< 中的准备工作多么精确，大约有 500 或更多字节丢失，写入了一个不完整的图像文件。
内存中的某处存在，而且必须存在，我需要的关于已上传二进制文件及其句柄的完整信息。但是从 Asio classes 中提取它似乎不必要地棘手。
这就是我使用 Boost Asio 取得的进展。就我而言，这是。我想要的，这里没有我的答案。
我的结果看起来像...
POST /post HTTP/1.1
Host: localhost:3003
User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:62.0)
Gecko/20100101 Firefox/62.0
Accept: */*
Accept-Language: en-US,en;q=0.5
Accept-Encoding: gzip, deflate
Referer: http://localhost:3003/profile
Content-type: multipart/form-data
Content-Length: 14708
Cookie: mycookie=7bdbed41954cd4133a172acb92988e58
Connection: keep-alive
-----------------------------4636945214860352321751082034
...
binary characters...
...
-----------------------------4636945214860352321751082034
购自
boost::asio::async_read(
socket_,
strmbuffer_,
boost::asio::transfer_exactly(bytes_to_transfer),
strand_.wrap(
[this, self](boost::system::error_code ec, std::size_t bytes_transferred)
{
std::stringstream ss;
ss << buffer_data; // from socket_.async_read_some()
ss << &strmbuffer_; // now stringstream contains everything
// the character routine which writes the above
// and which i use for output...
std::string output_file = "../../upload/test.png";
std::ofstream outfile(output_file);
char c;
unsigned bl = boundary.length();
bool endfile = false;
unsigned bufsize = 512;
if(outfile){
char buffer[bufsize];
while(!endfile){
// here looks like below
// to find and pass the first boundary
} // then stream continues...
while(!endfile){
unsigned j = 0;
unsigned k;
memset(buffer, 0, bufsize); // redundant
while(j < bufsize && ss.get(c) && !endfile){
buffer[j] = c;
k = 0;
while(boundary[bl - 1 - k] == buffer[j - k]){
if(k >= bl - 1){
endfile = true;
break;
}
k++;
}
j++;
}
outfile.write(buffer, j);
j = 0;
}
}
}
);
...本质上。因此，接收
socket_.async_read_some()
给我一个
boost::array<char, 8192> buffer_;
这给了我 http 请求信息。但是在multipart/form-data的情况下，它读过了第一个边界，这意味着下一个read()看不到它。啊！ （async_read_until() 也是如此。）因此，在
boost::asio::async_read()
我转换
boost::asio::streambuf strmbuffer_;
到字符串流并将它们加在一起以获得上面的 std::cout 结果。
我根本不相信我应该使用 stringstream。但是上面的例程（使用 stringstream）在 Boost::Beast 中运行良好。它不在 Asio 中。不幸的是，在 Beast 中接收 http 请求的 string_body 类型有大小限制，我相信是 1 兆。不知道如何更改它。
我在任何地方都找不到关于这个主题的信息。或许，情报太危险了。如果他们告诉我，他们就得杀了我。我应该在 Asio 中使用什么将二进制数据写入磁盘？
默认情况下，HTTP 请求解析器以 1 兆字节的限制开始。这是为了防止客户端发送非常大或无穷无尽的 body 数据的资源耗尽攻击。您可以通过使用所需的最大值调用 parser::body_limit 来轻松更改此限制。这在文档中有描述：
https://www.boost.org/doc/libs/1_68_0/libs/beast/doc/html/beast/ref/boost__beast__http__parser/body_limit.html https://www.boost.org/doc/libs/1_68_0/libs/beast/doc/html/beast/using_http/buffer_oriented_parsing.html
为了调整解析器参数，例如 body 限制（或 header 限制），您需要使用 "parser stream operation" 界面。这在这里解释：
我会 post 我自己的部分解决方案。它在 14.2kb png 上没有错误。高于此值可能会导致段错误，除非调整 'magic' 数字，如下所示。
我正在使用 Boost Asio HTTP 服务器示例 C++11。
在connection.hpp中，更改...
//boost::array<char, 8192> buffer_;
boost::array<char, 512> buffer_;
此外，添加...
boost::asio::streambuf strmbuffer_;
在connection.cpp中，这里是connection::handle_read()...
void connection::handle_read(const boost::system::error_code& e, std::size_t bytes_transferred)
{
if (!e)
{
//*** buffer_.data() for this file ***
//
//POST /post HTTP/1.1
//Host: localhost:3003
//User-Agent: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:62.0) Gecko/20100101 Firefox/62.0
//Accept: */*
//Accept-Language: en-US,en;q=0.5
//Accept-Encoding: gzip, deflate
//Referer: http://localhost:3003/profile
//Content-type: multipart/form-data
//Content-Length: 14710
//Cookie: knowstoryadmin=7bdbed41954cd4133a172acb92988e58
//Connection: keep-alive
//
//-----------------------------14071968205478138611648202646
//Content-Disposition: form-data; name="admin_profile_image_load"; filename="tlc-logo.png"
//Content-Type: image/png
//
//�PNG
//▒
std::stringstream strm1;
std::string buffer_data = buffer_.data();
strm1 << buffer_data;
std::string method;
std::smatch match_method;
std::regex regex_method ("\b([^ ]*)( )([^ ]*)( HTTP/1.1)([^ ]*)");
std::string content_type;
std::smatch match_content_type;
std::regex regex_content_type ("\b(Content-type: )([^ ]*)");
std::string line;
while (std::getline(strm1, line)) {
if (std::regex_search(line, match_method, regex_method)) {
method = match_method[0];
method = method.substr(0, method.find(' '));
boost::trim(method);
//std::cout << method << std::endl;
}
if (std::regex_search(line, match_content_type, regex_content_type)) {
content_type = match_content_type[0];
boost::erase_all(content_type, "Content-type:");
boost::trim(content_type);
//std::cout << content_type << std::endl;
}
}
if (method == "POST") {
if (content_type == "multipart/form-data") {
std::string content_length;
std::smatch match_content_length;
std::regex regex_content_length ("\b(Content-Length: )([^ ]*)");
std::string filename;
std::smatch match_filename;
std::regex regex_filename ("\b(filename)([^ ]*)");
std::string action;
std::smatch match_action;
std::regex regex_action ("\b(name)([^ ]*)");
std::string boundary;
std::smatch match_boundary;
std::regex regex_boundary ("([-]{10,}[0-9]{10,})");
std::string line;
strm1.clear();
strm1 << buffer_data;
while (std::getline(strm1, line)) {
if (std::regex_search(line, match_content_length, regex_content_length)) {
//Content-Length: 14710
content_length = match_content_length[0];
boost::erase_all(content_length, "Content-Length:");
boost::trim(content_length);
//std::cout << content_length << std::endl;
}
if (std::regex_search(line, match_filename, regex_filename)) {
filename = match_filename[0];
boost::erase_all(filename, "\"");
boost::erase_all(action, ";");
boost::erase_all(filename, "filename=");
std::size_t found = filename.find_last_of(".");
std::size_t len = filename.length();
std::string mime = filename.substr(found, len);
boost::trim(filename);
//std::cout << filename << std::endl;
//std::cout << mime << std::endl;
}
if (std::regex_search(line, match_action, regex_action)) {
action = match_action[0];
boost::erase_all(action, "\"");
boost::erase_all(action, ";");
boost::erase_all(action, "name=");
boost::trim(action);
//std::cout << action << std::endl;
}
if (std::regex_search(line, match_boundary, regex_boundary)) {
boundary = match_boundary[0];
boost::trim(boundary);
//std::cout << boundary << std::endl;
}
}
//pubseekpos works as expected, but useless here
//strmbuffer_.pubseekpos(bytes_transferred);
//content length minus bytes_transfered does NOT yield
//the right result. The number, 392, is the 'magic' number
//adjustment for this file size, approx 14.2kb, that i found
//by trial and error.
//Adjusting the magic number is necessary for every image size
//in order to avoid a segfault.
//bytes_transferred, for each read(), is the only 'reliable'
//number with which to work, as far as i know.
//If there is a brainier way of calculating this,
//i don't care, anymore.
int n_content_length = std::stoi(content_length);
int transfer = n_content_length - bytes_transferred + 392;
auto self(shared_from_this());
boost::asio::async_read(
socket_,
strmbuffer_,
boost::asio::transfer_exactly(transfer),
strand_.wrap(
[this, self, boundary](boost::system::error_code ec, std::size_t bytes_transferred)
{
std::stringstream strm2;
strm2 << &strmbuffer_;
std::string line;
unsigned bufsize = 512;
while (std::getline(strm2, line))
{
if(line.length() == 1){
std::string output_file = "../../upload/test.png";
std::ofstream outfile(output_file);
char c;
unsigned bl = boundary.length();
bool endfile = false;
if(outfile){
char buffer[bufsize];
while(!endfile){
unsigned j = 0;
unsigned k;
while(j < bufsize && strm2.get(c) && !endfile){
buffer[j] = c;
k = 0;
while(boundary[bl - 1 - k] == buffer[j - k]){
if(k >= bl - 1){
endfile = true;
break;
}
k++;
}
j++;
}
outfile.write(buffer, j);
j = 0;
};
outfile.close();
std::cout << "outfile close" << std::endl;
break;
}
}
}
}
)
);
}
else {
// POST AJAX
std::cout << "connection " << method << std::endl;
}
}
else {
boost::tribool result;
boost::tie(result, boost::tuples::ignore) = request_parser_.parse(
request_, buffer_.data(), buffer_.data() + bytes_transferred);
if (result)
{
request_handler_.handle_request(
request_,
reply_);
boost::asio::async_write(
socket_,
reply_.to_buffers(),
strand_.wrap(
boost::bind(
&connection::handle_write,
shared_from_this(),
boost::asio::placeholders::error)
));
}
else if (!result)
{
reply_ = reply::stock_reply(reply::bad_request);
boost::asio::async_write(
socket_,
reply_.to_buffers(),
strand_.wrap(
boost::bind(&connection::handle_write, shared_from_this(),
boost::asio::placeholders::error)));
}
else
{
socket_.async_read_some(
boost::asio::buffer(buffer_),
strand_.wrap(
boost::bind(
&connection::handle_read,
shared_from_this(),
boost::asio::placeholders::error,
boost::asio::placeholders::bytes_transferred)));
}
}
}
}
对于这个 Asio 示例，此部分解决方案相当 'unobtrusive'。 request_handler class 不变，服务于 GET。
在connection::start()中，我尝试了async_read。但结果更难以预测。这意味着我必须附加两个字符串，一个由 strmbuffer1_ 制成，另一个由 strmbuffer2_ 制成，以便在文件输出循环中一起构造（破解）流。无论我在 cout<< 中的准备工作多么精确，大约有 500 或更多字节丢失，写入了一个不完整的图像文件。
内存中的某处存在，而且必须存在，我需要的关于已上传二进制文件及其句柄的完整信息。但是从 Asio classes 中提取它似乎不必要地棘手。
这就是我使用 Boost Asio 取得的进展。就我而言，这是。我想要的，这里没有我的答案。