httpfetch.h

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// Luanti
// SPDX-License-Identifier: LGPL-2.1-or-later
// Copyright (C) 2013 celeron55, Perttu Ahola <celeron55@gmail.com>
 
#pragma once
 
#include <vector>
#include "util/string.h"
 
// These can be used in place of "caller" in to specify special handling.
// Discard result (used as default value of "caller").
#define HTTPFETCH_DISCARD 0
// Indicates that the result should not be discarded when performing a
// synchronous request (since a real caller ID is not needed for synchronous
// requests because the result does not have to be retrieved later).
#define HTTPFETCH_SYNC 1
// Print response body to console if the server returns an error code.
#define HTTPFETCH_PRINT_ERR 2
// Start of regular allocated caller IDs.
#define HTTPFETCH_CID_START 3
 
namespace {
        // lower bound for curl_timeout (see also settingtypes.txt)
        constexpr long MIN_HTTPFETCH_TIMEOUT_INTERACTIVE = 1000;
        // lower bound for curl_file_download_timeout
        constexpr long MIN_HTTPFETCH_TIMEOUT = 5000;
}
 
//  Methods
enum HttpMethod : u8
{
        HTTP_GET,
        HTTP_HEAD,
        HTTP_POST,
        HTTP_PUT,
        HTTP_PATCH,
        HTTP_DELETE,
};
 
struct HTTPFetchRequest
{
        std::string url = "";
 
        // Identifies the caller (for asynchronous requests)
        // Ignored by httpfetch_sync
        u64 caller = HTTPFETCH_DISCARD;
 
        // Some number that identifies the request
        // (when the same caller issues multiple httpfetch_async calls)
        u64 request_id = 0;
 
        // Timeout for the whole transfer, in milliseconds
        long timeout;
 
        // Timeout for the connection phase, in milliseconds
        long connect_timeout;
 
        // Indicates if this is multipart/form-data or
        // application/x-www-form-urlencoded. Not allowed for GET.
        bool multipart = false;
 
        // Method to use
        HttpMethod method = HTTP_GET;
 
        // Fields of the request
        StringMap fields;
 
        // Raw data of the request (instead of fields, ignored if multipart)
        std::string raw_data;
 
        // If not empty, should contain entries such as "Accept: text/html"
        std::vector<std::string> extra_headers;
 
        // User agent to send
        std::string useragent;
 
        HTTPFetchRequest();
};
 
struct HTTPFetchResult
{
        bool succeeded = false;
        bool timeout = false;
        long response_code = 0;
        std::string data = "";
        // The caller and request_id from the corresponding HTTPFetchRequest.
        u64 caller = HTTPFETCH_DISCARD;
        u64 request_id = 0;
 
        HTTPFetchResult() = default;
 
        HTTPFetchResult(const HTTPFetchRequest &fetch_request) :
                        caller(fetch_request.caller), request_id(fetch_request.request_id)
        {
        }
};
 
// Initializes the httpfetch module
void httpfetch_init(int parallel_limit);
 
// Stops the httpfetch thread and cleans up resources
void httpfetch_cleanup();
 
// Starts an asynchronous HTTP fetch request
void httpfetch_async(const HTTPFetchRequest &fetch_request);
 
// If any fetch for the given caller ID is complete, removes it from the
// result queue, sets the fetch result and returns true. Otherwise returns false.
bool httpfetch_async_get(u64 caller, HTTPFetchResult &fetch_result);
 
// Allocates a caller ID for httpfetch_async
// Not required if you want to set caller = HTTPFETCH_DISCARD
u64 httpfetch_caller_alloc();
 
// Allocates a non-predictable caller ID for httpfetch_async
u64 httpfetch_caller_alloc_secure();
 
// Frees a caller ID allocated with httpfetch_caller_alloc
// Note: This can be expensive, because the httpfetch thread is told
// to stop any ongoing fetches for the given caller.
void httpfetch_caller_free(u64 caller);
 
// Performs a synchronous HTTP request that is interruptible if the current
// thread is a Thread object. interval is the completion check interval in ms.
// This blocks and therefore should only be used from background threads.
// Returned is whether the request completed without interruption.
bool httpfetch_sync_interruptible(const HTTPFetchRequest &fetch_request,
                HTTPFetchResult &fetch_result, long interval = 100);