danicoin/external/glim/curl.hpp
Thomas Winget 90d6f8bf62 Adding libglim as an external library
libglim is an Apache-licensed C++ wrapper for lmdb, and rather than
rolling our own it seems prudent to use it.

Note: lmdb is not included in it, and unless something happens as did
with libunbound, should be installed via each OS' package manager or
equivalent.
2015-01-04 18:41:44 -08:00

304 lines
14 KiB
C++

/** \file
* Very simple header-only wrapper around libcurl.\n
* See also: https://github.com/venam/Browser\n
* See also: https://github.com/mologie/curl-asio\n
* See also: http://thread.gmane.org/gmane.comp.web.curl.library/1322 (this one uses a temporary file). */
#ifndef _GLIM_CURL_INCLUDED
#define _GLIM_CURL_INCLUDED
#include "gstring.hpp"
#include "exception.hpp"
#include <curl/curl.h>
#include <algorithm>
#include <functional>
#include <string.h>
#include <stdint.h>
namespace glim {
inline size_t curlWriteToString (void *buffer, size_t size, size_t nmemb, void *userp) {
((std::string*) userp)->append ((const char*) buffer, size * nmemb);
return size * nmemb;};
inline size_t curlReadFromString (void *ptr, size_t size, size_t nmemb, void *userdata);
inline size_t curlReadFromGString (void *ptr, size_t size, size_t nmemb, void *userdata);
inline size_t curlWriteHeader (void *ptr, size_t size, size_t nmemb, void *curlPtr);
inline int curlDebugCB (CURL* curl, curl_infotype type, char* bytes, size_t size, void* curlPtr);
/**
Simple HTTP requests using cURL.
Example: \code
std::string w3 = glim::Curl() .http ("http://www.w3.org/") .go().str();
\endcode
*/
class Curl {
protected:
Curl (const Curl&): _curl (NULL), _headers (NULL), _sent (0), _needs_cleanup (true) {} // No copying.
public:
struct PerformError: public glim::Exception {
PerformError (const char* message, const char* file, int32_t line):
glim::Exception (message, file, line) {}
};
struct GetinfoError: public glim::Exception {
CURLcode _code; std::string _error;
GetinfoError (CURLcode code, const std::string& error, const char* file, int32_t line):
glim::Exception (error, file, line),
_code (code), _error (error) {}
};
public:
CURL* _curl;
struct curl_slist *_headers;
std::function<void (const char* header, int len)> _headerListener;
std::function<void (curl_infotype type, char* bytes, size_t size)> _debugListener;
std::string _sendStr; ///< We're using `std::string` instead of `gstring` in order to support payloads larger than 16 MiB.
glim::gstring _sendGStr; ///< `gstring::view` and `gstring::ref` allow us to zero-copy.
uint32_t _sent;
std::string _got;
bool _needs_cleanup:1; ///< ~Curl will do `curl_easy_cleanup` if `true`.
char _errorBuf[CURL_ERROR_SIZE];
Curl (Curl&&) = default;
/// @param cleanup can be turned off if the cURL is freed elsewhere.
Curl (bool cleanup = true): _curl (curl_easy_init()), _headers (NULL), _sent (0), _needs_cleanup (cleanup) {
curl_easy_setopt (_curl, CURLOPT_NOSIGNAL, 1L); // required per http://curl.haxx.se/libcurl/c/libcurl-tutorial.html#Multi-threading
*_errorBuf = 0;}
/// Wraps an existing handle (will invoke `curl_easy_cleanup` nevertheless).
/// @param cleanup can be turned off if the cURL is freed elsewhere.
Curl (CURL* curl, bool cleanup = true): _curl (curl), _headers (NULL), _sent (0), _needs_cleanup (cleanup) {
curl_easy_setopt (_curl, CURLOPT_NOSIGNAL, 1L); // required per http://curl.haxx.se/libcurl/c/libcurl-tutorial.html#Multi-threading
*_errorBuf = 0;}
~Curl(){
if (_headers) {curl_slist_free_all (_headers); _headers = NULL;}
if (_curl) {if (_needs_cleanup) curl_easy_cleanup (_curl); _curl = NULL;}
}
/** Stores the content to be sent into an `std::string` inside `Curl`.
* NB: In order to have an effect this method should be used *before* the `http()` and `smtp()` methods. */
template<typename STR> Curl& send (STR&& text) {
_sendStr = std::forward<STR> (text);
_sendGStr.clear();
_sent = 0;
return *this;}
/// Adds "Content-Type" header into `_headers`.
Curl& contentType (const char* ct) {
char ctb[64]; gstring cth (sizeof (ctb), ctb, false, 0);
cth << "Content-Type: " << ct << "\r\n";
_headers = curl_slist_append (_headers, cth.c_str());
return *this;
}
/// @param fullHeader is a full HTTP header and a newline, e.g. "User-Agent: Me\r\n".
Curl& header (const char* fullHeader) {
_headers = curl_slist_append (_headers, fullHeader);
return *this;
}
/**
Sets the majority of options for the http request.
NB: If `send` was used with a non-empty string then `http` will use `CURLOPT_UPLOAD`, setting http method to `PUT` (use the `method()` to override).
\n
Example: \code
glim::Curl curl;
curl.http (url.c_str()) .go();
std::cout << curl.status() << std::endl << curl.str() << std::endl;
\endcode
*/
Curl& http (const char* url, int timeoutSec = 20) {
curl_easy_setopt (_curl, CURLOPT_NOSIGNAL, 1L); // required per http://curl.haxx.se/libcurl/c/libcurl-tutorial.html#Multi-threading
curl_easy_setopt (_curl, CURLOPT_URL, url);
curl_easy_setopt (_curl, CURLOPT_WRITEFUNCTION, curlWriteToString);
curl_easy_setopt (_curl, CURLOPT_WRITEDATA, &_got);
curl_easy_setopt (_curl, CURLOPT_TIMEOUT, timeoutSec);
curl_easy_setopt (_curl, CURLOPT_PROTOCOLS, CURLPROTO_HTTP);
curl_easy_setopt (_curl, CURLOPT_ERRORBUFFER, _errorBuf);
if (_sendStr.size() || _sendGStr.size()) {
curl_easy_setopt (_curl, CURLOPT_UPLOAD, 1L); // http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTUPLOAD
if (_sendStr.size()) {
curl_easy_setopt (_curl, CURLOPT_INFILESIZE, (long) _sendStr.size());
curl_easy_setopt (_curl, CURLOPT_READFUNCTION, curlReadFromString);
} else {
curl_easy_setopt (_curl, CURLOPT_INFILESIZE, (long) _sendGStr.size());
curl_easy_setopt (_curl, CURLOPT_READFUNCTION, curlReadFromGString);}
curl_easy_setopt (_curl, CURLOPT_READDATA, this);}
if (_headers)
curl_easy_setopt (_curl, CURLOPT_HTTPHEADER, _headers); // http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTHTTPHEADER
return *this;
}
/**
Set options for smtp request.
Example: \code
long rc = glim::Curl().send ("Subject: subject\r\n\r\n" "text\r\n") .smtp ("from", "to") .go().status();
if (rc != 250) std::cerr << "Error sending email: " << rc << std::endl;
\endcode */
Curl& smtp (const char* from, const char* to) {
curl_easy_setopt (_curl, CURLOPT_NOSIGNAL, 1L); // required per http://curl.haxx.se/libcurl/c/libcurl-tutorial.html#Multi-threading
curl_easy_setopt (_curl, CURLOPT_URL, "smtp://127.0.0.1");
if (from) curl_easy_setopt (_curl, CURLOPT_MAIL_FROM, from);
bcc (to);
if (_headers) curl_easy_setopt (_curl, CURLOPT_MAIL_RCPT, _headers);
curl_easy_setopt (_curl, CURLOPT_WRITEFUNCTION, curlWriteToString);
curl_easy_setopt (_curl, CURLOPT_WRITEDATA, &_got);
if (_sendStr.size()) {
curl_easy_setopt (_curl, CURLOPT_INFILESIZE, (long) _sendStr.size());
curl_easy_setopt (_curl, CURLOPT_READFUNCTION, curlReadFromString);
curl_easy_setopt (_curl, CURLOPT_READDATA, this);
} else if (_sendGStr.size()) {
curl_easy_setopt (_curl, CURLOPT_INFILESIZE, (long) _sendGStr.size());
curl_easy_setopt (_curl, CURLOPT_READFUNCTION, curlReadFromGString);
curl_easy_setopt (_curl, CURLOPT_READDATA, this);
}
curl_easy_setopt (_curl, CURLOPT_UPLOAD, 1L); // cURL now needs this to actually send the email, cf. "http://curl.haxx.se/mail/lib-2013-12/0152.html".
return *this;
}
/** Add SMTP recipient to the `_headers` (which are then set into `CURLOPT_MAIL_RCPT` by the `Curl::smtp`).
* NB: Should be used *before* the `Curl::smtp`! */
Curl& bcc (const char* to) {
if (to) _headers = curl_slist_append (_headers, to);
return *this;
}
/**
Uses `CURLOPT_CUSTOMREQUEST` to set the http method.
Can be used both before and after the `http` method.\n
Example sending a POST request to ElasticSearch: \code
glim::Curl curl;
curl.send (C2GSTRING (R"({"query":{"match_all":{}},"facets":{"tags":{"terms":{"field":"tags","size":1000}}}})"));
curl.method ("POST") .http ("http://127.0.0.1:9200/froples/frople/_search", 120);
if (curl.verbose().go().status() != 200) GTHROW ("Error fetching tags: " + std::to_string (curl.status()) + ", " + curl.str());
cout << curl.gstr() << endl;
\endcode */
Curl& method (const char* method) {
curl_easy_setopt (_curl, CURLOPT_CUSTOMREQUEST, method);
return *this;
}
/** Setup a handler to process the headers cURL gets from the response.
* "The header callback will be called once for each header and only complete header lines are passed on to the callback".\n
* See http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTHEADERFUNCTION */
Curl& headerListener (std::function<void (const char* header, int len)> listener) {
curl_easy_setopt (_curl, CURLOPT_HEADERFUNCTION, curlWriteHeader);
curl_easy_setopt (_curl, CURLOPT_WRITEHEADER, this);
_headerListener = listener;
return *this;
}
/** Setup a handler to get the debug messages generated by cURL.
* See http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTDEBUGFUNCTION */
Curl& debugListener (std::function<void (curl_infotype type, char* bytes, size_t size)> listener) {
curl_easy_setopt (_curl, CURLOPT_DEBUGFUNCTION, curlDebugCB);
curl_easy_setopt (_curl, CURLOPT_DEBUGDATA, this);
_debugListener = listener;
return verbose (true);
}
/**
Setup a handler to get some of the debug messages generated by cURL.
Listener gets a formatted text: outbound data is prepended with "> " and inbound with "< ".\n
Usage example: \code
auto curlDebug = std::make_shared<std::string>();
curl->debugListenerF ([curlDebug](const char* bytes, size_t size) {curlDebug->append (bytes, size);});
...
if (curl->status() != 200) std::cerr << "cURL status != 200; debug follows: " << *curlDebug << std::endl;
\endcode
See http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTDEBUGFUNCTION
@param listener The receiver of the debug information.
@param data Whether to pass the data (`CURLINFO_DATA_IN`, `CURLINFO_DATA_OUT`) to the `listener`.
*/
Curl& debugListenerF (std::function<void (const char* bytes, size_t size)> listener, bool data = false) {
return debugListener ([listener/* = std::move (listener)*/,data] (curl_infotype type, char* bytes, size_t size) {
GSTRING_ON_STACK (buf, 256);
auto prepend = [&](const char* prefix) {
buf << prefix; for (char *p = bytes, *end = bytes + size; p < end; ++p) {buf << *p; if (*p == '\n' && p + 2 < end) buf << prefix;}};
if (type == CURLINFO_HEADER_IN || (type == CURLINFO_DATA_IN && data)) prepend ("< ");
else if (type == CURLINFO_HEADER_OUT || (type == CURLINFO_DATA_OUT && data)) prepend ("> ");
listener (buf.c_str(), buf.size());
});
}
/// Whether to print debug information to `CURLOPT_STDERR`.
/// Note that when `debugListener` is used, verbose output will go to the listener and not to `CURLOPT_STDERR`.
Curl& verbose (bool on = true) {
curl_easy_setopt (_curl, CURLOPT_VERBOSE, on ? 1L : 0L);
return *this;
}
/// Reset the buffers and perform the cURL request.
Curl& go() {
_got.clear();
*_errorBuf = 0;
if (curl_easy_perform (_curl)) throw PerformError (_errorBuf, __FILE__, __LINE__);
return *this;
}
/// The contents of the response.
const std::string& str() const {return _got;}
/// CString of `str`.
const char* c_str() const {return _got.c_str();}
/// Returns a gstring "view" into `str`.
gstring gstr() const {return gstring (0, (void*) _got.data(), false, _got.size());}
/// The status of the response (For HTTP it's 200 ok, 404 not found, 500 error, etc).
long status() const {
long status; CURLcode err = curl_easy_getinfo (_curl, CURLINFO_RESPONSE_CODE, &status);
if (err) {
GSTRING_ON_STACK (message, 128) << "CURL error " << (int) err << ": " << curl_easy_strerror (err);
throw GetinfoError (err, message.str(), __FILE__, __LINE__);
}
return status;}
};
/** Moves the content to be sent into a `glim::gstring` inside `Curl`.
* NB: In order to have an effect this method should be used *before* the `http()` and `smtp()` methods. */
template<> inline Curl& Curl::send<gstring> (gstring&& text) {
_sendStr.clear();
_sendGStr = std::move (text);
_sent = 0;
return *this;}
inline size_t curlReadFromString (void *ptr, size_t size, size_t nmemb, void *userdata) {
Curl* curl = (Curl*) userdata;
size_t len = std::min (curl->_sendStr.size() - curl->_sent, size * nmemb);
if (len) memcpy (ptr, curl->_sendStr.data() + curl->_sent, len);
curl->_sent += len;
return len;}
inline size_t curlReadFromGString (void *ptr, size_t size, size_t nmemb, void *userdata) {
Curl* curl = (Curl*) userdata;
size_t len = std::min (curl->_sendGStr.size() - curl->_sent, size * nmemb);
if (len) memcpy (ptr, curl->_sendGStr.data() + curl->_sent, len);
curl->_sent += len;
return len;}
// http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTHEADERFUNCTION
inline size_t curlWriteHeader (void *ptr, size_t size, size_t nmemb, void *curlPtr) {
Curl* curl = (Curl*) curlPtr;
std::function<void (const char* header, int len)>& listener = curl->_headerListener;
int len = size * nmemb;
if (listener) listener ((const char*) ptr, len);
return (size_t) len;
}
// http://curl.haxx.se/libcurl/c/curl_easy_setopt.html#CURLOPTDEBUGFUNCTION
inline int curlDebugCB (CURL*, curl_infotype type, char* bytes, size_t size, void* curlPtr) {
Curl* curl = (Curl*) curlPtr;
auto& listener = curl->_debugListener;
if (listener) listener (type, bytes, size);
return 0;
}
/// Example: std::string w3 = glim::curl2str ("http://www.w3.org/");
inline std::string curl2str (const char* url, int timeoutSec = 20) {
try {
return glim::Curl().http (url, timeoutSec) .go().str();
} catch (const std::exception&) {}
return std::string();
}
}
#endif