path: root/src/api.c

#define DC_LOGIN_FORMAT "{\"login\":\"%s\",\"password\":\"%s\",\"undelete\":false,\"captcha_key\":null,\"login_source\":null,\"gift_code_sku_id\":null}"
#define DC_COMPILE_INFO __VERSION__ " "  __BASE_FILE__ " " __FILE__ " " __TIMESTAMP__
#define DC_IDENTIFY_FORMAT "{\"op\":2,\"d\":{\"token\":\"%s\",\"intents\":%d" /* ",\"presence\":{\"since\":null,\"status\":\"online\",\"afk\":false,\"activities\":{\"name\":\":pager: Connected via discord.c\",\"type\":4}}" */ ",\"properties\":{\"$os\":\"posix\",\"$browser\":\"discord.c\",\"$device\":\"" DC_COMPILE_INFO "\"}}}" /* this exposes we are discord.c, if this turns out to get people banned, change to whatever an official client sends */
#define DC_USER_AGENT "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/74.0.3729.131 Safari/537.36" /* this is so we can fool the login system */
#define DC_SERVER_ADDRESS "discord.com"
#define DC_SERVER_PORT 443
#define DC_SERVER_SSL 1
#define DC_SERVER_ORIGIN "https://discord.com"
#define DC_WS_ADDRESS "gateway.discord.gg"
#define DC_WS_PORT DC_SERVER_PORT
#define DC_WS_SSL DC_SERVER_SSL
#define DC_WS_ORIGIN DC_SERVER_ORIGIN
#define DC_WS_PATH "/" /* add ?v=9&encoding=json in case of problems */
#define DC_API_PREFIX "/api/v9/"
#define DC_LWS_ABLE_TO_PARSE_HEADERS 1
/* libwebsockets information: libwebsockets works with event loops and discord.c primary targets debian for building (it must work on debian), but debian does not ship libwebsockets with glib or libevent event loop support, so loops are implemented in the classic poll() style. this reduces performance probably. if you use discord.c API with support for a platform specific event loop, you may rewrite LWS to do things differently. currently calls into API (dc_api_i and dc_api_o) will both do LWS stuff. */
void dc_api_stack (struct dc_api_io i) { /* stack output struct to be delivered via dc_api_o 2usr */
	DC_MR(i.program->api_ios);
	i.program->api_ios[i.program->api_ios_length] = malloc(sizeof(i));
	*(i.program->api_ios[i.program->api_ios_length++]) = i;
	return;
}
signed char dc_json_cb (struct lejp_ctx * ctx, char /* enum lejp_callbacks */ reason) {
	enum dc_json_paths path = ctx->path_match-1; /* we assume that the order of incoming data is */
	struct dc_lws_pass * pass = ctx->user; /* correct. op should come first, etc. */
	pass->json_reason = reason;
	if (reason == LEJPCB_FAILED) {
		DC_API_IO_GC(pass->api_io);
		pass->packet = DC_NONE;
		pass->parsing_status = NULL;
		return '\0';
	}
	fprintf(stderr, "JSON: %s reason: %d %.*s\n", ctx->path, reason, 40, pass->cp);
	if (ctx->path_match && reason & LEJP_FLAG_CB_IS_VALUE) {
		switch (path) {
			case DC_JSON_S: /* packet sequence number */
				pass->api_io.client->last_packet = strtoull(ctx->buf, NULL, 10);
				break;
			case DC_JSON_OP:
				DC_API_IO_GC(pass->api_io); /* frees all unfinished parsing objects */
				pass->packet = atoi(ctx->buf);
				break;
			case DC_JSON_PING:
				pass->api_io.client->ping_interval = atoi(ctx->buf);
				break;
			default: /* to prevent warning: enumeration value DC_JSON_* not handled */
				break;
		}
		return '\0';
	}
	if (pass->packet == DC_NONE) /* useless to do anything if we haven't received packet type */
		return '\0';
	if (reason == LEJPCB_COMPLETE) { /* gr8, fin, call back to api */
		if (!pass->parsing_status) { /* some stuff is fully handled in switch (pass->pkt) */
			pass->packet = DC_NONE;
			return '\0';
		}
		*pass->parsing_status &= ~DC_IN_PROGRESS;
		pass->api_io.status |= DC_FROM_LWS; /* we callback on FAILED too, so that we don't */
		// dc_api_io(pass->api_io); /* end up with a memory leak if we allocated a struct */
		pass->api_io.status &= ~DC_FROM_LWS;
		pass->parsing_status = NULL;
		pass->packet = DC_NONE;
		return '\0';
	}
	switch (pass->packet) { /* we fill in structs, set DC_INCOMPLETE and pass->parsing_status */
		case DC_PING:
			dc_handle_ping(pass->api_io, pass /* this is just so it's not NULL */);
			break;
		default:
			break;
	}
	return '\0'; /* by the way, what does the return value do here? write in the comments below (; */
}
static int dc_lws_cb (struct lws * wsi, enum lws_callback_reasons rs, void * us, void * in, size_t len) {
	struct dc_lws_pass * pass = (struct dc_lws_pass *) us;
	unsigned char buf[LWS_PRE+DC_LWS_BUF+1]; /* whooh, boy, this is more than a meg of stack! */
	switch (rs) {
		case LWS_CALLBACK_CLIENT_CONNECTION_ERROR: /* TODO: handle and report somehow */
			if (pass) {
				pass->api_io.status = DC_NET_ERROR;
				pass->wsi = NULL;
				pass->api_io.status |= DC_FROM_LWS;
				dc_api_i(pass->api_io);
				pass->api_io.status &= ~DC_FROM_LWS;
			}
			lwsl_err("CLIENT_CONNECTION_ERROR: %s\n", in ? (char *) in : "(null)");
			break;
		case LWS_CALLBACK_CLIENT_APPEND_HANDSHAKE_HEADER: /* lws gives us len space after *in */
			;
			unsigned char ** p = (unsigned char **) in, * end = (*p)+len;
			for (int i = 0; i < DC_LWS_HEADERS_LENGTH; i++)
				if (pass->headers[i][0])
					if (lws_add_http_header_by_name(wsi, (const unsigned char *) dc_lws_headers[i], (const unsigned char *) pass->headers[i], strlen(pass->headers[i]), p, end))
						return -1;
			char slen[32];
			snprintf(slen, 32, "%u", pass->body_length);
			if (lws_add_http_header_by_name(wsi, (const unsigned char *) "Content-Length:", (const unsigned char *) slen, strlen(slen), p, end))
				return -1;
			if (!lws_http_is_redirected_to_get(wsi)) {
				lwsl_user("doing POST flow\n");
				lws_client_http_body_pending(wsi, 1);
				lws_callback_on_writable(wsi);
			} else
				lwsl_user("doing GET flow, got redirected - this is a bug, report!\n");
			break;
		case LWS_CALLBACK_CLIENT_HTTP_WRITEABLE: /* see minimal post example on how to send */
			if (lws_http_is_redirected_to_get(wsi)) {
				fprintf(stderr, "http is redirected to get\n");
				break;	/* for setting avatar pictures or uploading files. Yecch */
			}
			fprintf(stderr, "LWS_CALLBACK_CLIENT_HTTP_WRITABLE, %d\n", pass->api_io.status);
			if (lws_write(wsi, (unsigned char *) pass->body, pass->body_length, LWS_WRITE_HTTP_FINAL) != (int) pass->body_length) { /* TODO: fix to allow sending large bodies */
				fprintf(stderr, "lws_write can't write that much!\n");
				return 1;
			}
			lws_client_http_body_pending(wsi, 0);
			if (pass->api_io.status & DC_MUST_FREE)
				free(pass->body);
			pass->body = NULL;
			pass->body_length = 0;
			break;
		case LWS_CALLBACK_ESTABLISHED_CLIENT_HTTP:
			pass->status = lws_http_client_http_response(wsi); /* 200 OK, 404 Not Found,...*/
			fprintf(stderr, "Connected with server response: %d\n", pass->status);
#ifdef DC_LWS_ABLE_TO_PARSE_HEADERS
			/* how to query custom headers (http 1.x only at the moment) */
			for (int i = 0; i < DC_LWS_HEADERS_LENGTH; i++) {
				pass->headers[i][0] = '\0'; /* to clear any headers we requested with */
				int n = lws_hdr_custom_length(wsi, dc_lws_headers[i], strlen(dc_lws_headers[i]));
				if (n < -1)
					lwsl_notice("Error with header %s.\n", dc_lws_headers[i]);
				else
					if (lws_hdr_custom_copy(wsi, pass->headers[i], DC_LWS_MAX_HEADER_LENGTH, dc_lws_headers[i], strlen(dc_lws_headers[i])) < 0)
						lwsl_notice("Header %s too long or non existent.\n", dc_lws_headers[i]);
					else
						lwsl_notice("%s %s\n", dc_lws_headers[i], pass->headers[i]);
			}
#endif
			break;
		case LWS_CALLBACK_RECEIVE_CLIENT_HTTP_READ: /* chunked body, without headers */
			fprintf(stderr, "RECEIVE_CLIENT_HTTP_READ: read %d\n", len);
			lwsl_hexdump_notice(in, len); /* for debugging purposes, kek */
			if (!(pass->api_io.status & DC_MUST_FREE)) { /* we start filling the ->body */
				pass->api_io.status |= DC_MUST_FREE; /* buffer, on end of wsi session */
				pass->body = NULL; /* dc_api_i is called from DC_CALLBACK_WSI_DESTROY */
			} /* if ->body from input was not freed and it should be, res body is appended */
			pass->body_length += len; /* if ->body was static, pointer is changed to NULL */
			pass->body = realloc(pass->body, pass->body_length + 1); /* normally - no edge */
			memcpy(pass->body+pass->body_length-len, in, len); /* case - resp body will be */
			pass->body[pass->body_length] = '\0'; /* on heap and freed on _DESTROY. */
			return 0; /* don't pass to lws_callback_http_dummy */
		case LWS_CALLBACK_RECEIVE_CLIENT_HTTP: /* uninterpreted http content */
			;
			char * ptr = (char *) buf + LWS_PRE; /* see, BEFORE the pointer - lower addr */
			int len2 /* DC_LWS_BUF again */ = sizeof(buf) - LWS_PRE;
			if (lws_http_client_read(wsi, &ptr, &len2) < 0) {
				fprintf(stderr, "lws_http_client_read -1\n");
				return -1;
			}
			return 0; /* don't pass to lws_callback_http_dummy */
		case LWS_CALLBACK_COMPLETED_CLIENT_HTTP:
			lwsl_user("LWS_CALLBACK_COMPLETED_CLIENT_HTTP\n");
			break;
		case LWS_CALLBACK_CLOSED_CLIENT_HTTP:
			lwsl_user("LWS_CALLBACK_CLOSED_CLIENT_HTTP\n");
			break;
		case LWS_CALLBACK_WSI_DESTROY: /* if I understand the docs correctly, this is allways */
			if (pass->api_io.pass != pass)
				fprintf(stderr, "[!!!] REPORT THIS BUG: pass->api_io.pass != pass\n");
			pass->api_io.status |= DC_FROM_LWS;
			dc_api_i(pass->api_io);
			pass->api_io.status &= ~DC_FROM_LWS;
			fprintf(stderr, "pass before freed is %p\n", (void *) pass);
			if (pass->api_io.status & DC_MUST_FREE) /* we still do this check in case */
				free(pass->body); /* _READ was not called and pointer was static */
			pass->api_io.client->pass = NULL;
			free(pass); /* called at the final moment when user pointer and wsi is still */
			break; /* accessible - we can free the struct that was passed in as a heap ptr */
		case LWS_CALLBACK_WSI_CREATE: /* first - outermost - call with wsi present */
			if (pass->api_io.client && pass->api_io.status & DC_SET_PASS) {
				fprintf(stderr, "pass->api_io.client->pass = pass\n");
				pass->api_io.client->pass = pass;
			}
			break;
		case LWS_CALLBACK_CLIENT_ESTABLISHED: /* websocket established */
			fprintf(stderr, "LWS_CALLBACK_CLIENT_ESTABLISHED\n");
			pass->api_io.status = DC_OK;
			pass->wsi = wsi;
			pass->api_io.status |= DC_FROM_LWS;
			dc_api_i(pass->api_io);
			pass->api_io.status &= ~DC_FROM_LWS;
			break;
		case LWS_CALLBACK_CLIENT_CLOSED: /* websocket closed */
			DC_API_IO_GC(pass->api_io); /* frees all unfinished parsing objects */
			pass->packet = DC_NONE;
			pass->api_io.status = DC_NET_ERROR;
			pass->wsi = NULL;
			pass->api_io.status |= DC_FROM_LWS;
			dc_api_i(pass->api_io);
			pass->api_io.status &= ~DC_FROM_LWS;
			break;
		case LWS_CALLBACK_CLIENT_RECEIVE: /* websocket receive, pass to json parser ? */
			fprintf(stdout, "%.*s", len, (const unsigned char *) in);
			fflush(stdout);
			if (pass->json_reason == LEJPCB_COMPLETE || pass->json_reason == LEJPCB_FAILED || !(pass->api_io.status & DC_LEJP_CONSTRUCTED)) { /* we regenerate a new context in case we didn't do that yet or in case the previous one finished parsing */
				pass->api_io.status |= DC_LEJP_CONSTRUCTED;
				pass->packet = DC_NONE;
				lejp_construct(&pass->json_ctx, dc_json_cb, us /* == (void *) pass */, (const char * const *) dc_json_paths, LWS_ARRAY_SIZE(dc_json_paths));
			} /* lejp_parse does return number of excess bytes after parsing json. but I */
			pass->len = len; /* assume that server sends in chunks that always terminate */
			pass->cp = in; /* when json object terminates. valve pls fix */
			lejp_parse(&pass->json_ctx, (const unsigned char *) in, len);
			break;
		case LWS_CALLBACK_CLIENT_WRITEABLE: /* invoke with lws_callback_on_writeable(wsi) 4 ws */
			memcpy(buf+LWS_PRE, pass->body, pass->body_length);
			(buf+LWS_PRE)[pass->body_length] = '\0';
			lwsl_hexdump_notice(buf+LWS_PRE, pass->body_length);
			if (lws_write(wsi, (unsigned char *) buf+LWS_PRE, pass->body_length, LWS_WRITE_BINARY) != (int) pass->body_length) {
				fprintf(stderr, "ws lws_write failed!\n");
				return -1;
			}
			break;
		default:
			break;
	}
	return lws_callback_http_dummy(wsi, rs, us, in, len);
}
void dc_api_i (struct dc_api_io i) { /* this function does not call attached functions, only output does that */
	struct lws_client_connect_info info;
	struct dc_lws_pass * pass;
	if (!i.program)
		return;
	if (i.program->lws_context && !(i.status & DC_FROM_LWS))
		lws_service(i.program->lws_context, 0); /* DO NOT CALL THIS FROM _cb! */
	switch (i.type) {
		case DC_API_MESSAGE:
			break;
		case DC_API_CHANNEL:
			break;
		case DC_API_GUILD:
			break;
		case DC_API_LOGIN: /* TODO: library currently only works for a single client */
			if (!i.program->clients_length) /* already attempted login */
				DC_MR(i.program->clients);
			i.program->clients[0] = i.client;
			i.program->clients_length = 1;
			memset(&info, 0, sizeof(info));
			info.context = i.program->lws_context;
#if DC_SERVER_SSL
			info.ssl_connection = LCCSCF_USE_SSL;
#endif
			info.port = DC_SERVER_PORT;
			info.address = DC_SERVER_ADDRESS;
			info.path = DC_API_PREFIX "auth/login";
			info.host = info.address;
			/* info.origin = DC_SERVER_ORIGIN; */ /* just don't send it */
			info.method = "POST";
			pass = calloc(1, sizeof(struct dc_lws_pass)); /* cb frees */
			fprintf(stderr, "allocated pass at %p\n", (void *) pass);
			i.status |= DC_MUST_FREE;
			pass->body_length = smprintf(&pass->body, DC_LOGIN_FORMAT, i.client->email, i.client->password);
			fprintf(stderr, "length: %u string: %s\n", pass->body_length, pass->body);
			i.type = DC_API_LOGIN_CB;
			i.status &= ~DC_SET_PASS; /* this is a HTTP request, pass is for websockets */
			memcpy(&pass->api_io, &i, sizeof(i));
			pass->api_io.pass = pass;
			strcpy(pass->headers[DC_LWS_CONTENT_TYPE], "application/json");
			info.userdata = pass;
#if DC_LWS_ABLE_TO_PARSE_HEADERS
			info.alpn = "http/1.1";
#endif
			info.protocol = dc_lws_protocols[0].name;
			if (i.client->authorization) /* attempt cookie login without user/pass */
				strcpy(pass->headers[DC_LWS_AUTHORIZATION], i.client->authorization);
			i.status = DC_UNSET /* we clear the status */;
			lws_client_connect_via_info(&info);
			break;
		case DC_API_LOGIN_CB:
#define DC_STACK_RETURN(x) do { i.client->status = x; dc_api_stack(i); return; } while (0)
			i.type = DC_API_LOGIN;
			i.status &= ~DC_OK;
			if (!i.pass->body) {
				i.client->status |= DC_REQUEST_FAILED;
				dc_api_stack(i);
				break;
			}
			fprintf(stderr, "DEBUG: %s\n", i.pass->body);
			if (strstr(i.pass->body, "INVALID_LOGIN"))
				DC_STACK_RETURN(DC_BAD_LOGIN);
			if (strstr(i.pass->body, "captcha-required"))
				DC_STACK_RETURN(DC_CAPTCHA_NEEDED);
			if (strstr(i.pass->body, "ACCOUNT_LOGIN_VERIFICATION_EMAIL"))
				DC_STACK_RETURN(DC_VERIFICATION_NEEDED);
			char * cp, * c2;
#define DC_LTS "\"token\": \""
			if (!(cp = strstr(i.pass->body, DC_LTS)+strlen(DC_LTS)) || !(c2 = strchr(cp+strlen(DC_LTS), '"')))
				DC_STACK_RETURN(DC_ERROR);
			c2[0] = '\0'; /* body is on heap, we can edit it */
			free(i.client->authorization); /* in case we set it previously */
			i.client->authorization = strdup(cp);
			fprintf(stderr, "got token %s\n", i.client->authorization);
			i.client->status |= DC_OK | DC_INCOMPLETE;
			dc_api_stack(i);
			/* we now have to connect to the websocket */
			goto ws; /* we could call dc_api_i but that just fills stack */
			break;
		case DC_API_WS:
			ws:
			memset(&info, 0, sizeof(info));
			info.context = i.program->lws_context;
			if (!info.context)
				fprintf(stderr, "[BUG] !!! !info.context\n");
			info.port = DC_WS_PORT;
			info.address = DC_WS_ADDRESS;
			info.path = DC_WS_PATH;
			info.host = info.address;
			info.origin = DC_WS_ORIGIN;
#if DC_WS_SSL
			info.ssl_connection = LCCSCF_USE_SSL;
#endif
			info.protocol = dc_lws_protocols[0].name;
			info.local_protocol_name = info.protocol;
			pass = calloc(1, sizeof(struct dc_lws_pass));
			i.type = DC_API_WS_CB;
			i.status |= DC_SET_PASS;
			memcpy(&pass->api_io, &i, sizeof(i));
			pass->api_io.pass = pass;
			info.userdata = pass;
			if (i.client->authorization) /* attempt cookie login without user/pass */
				strcpy(pass->headers[DC_LWS_AUTHORIZATION], i.client->authorization);
			fprintf(stderr, "starting websocket session\n");
			i.status = DC_UNSET; /* we clear the status */
			if (!lws_client_connect_via_info(&info)) {
				i.client->status = DC_NET_ERROR;
				dc_api_stack(i);
			}
			break;
		case DC_API_WS_CB:
			i.client->status &= ~(DC_NET_ERROR | DC_OK);
			i.client->status |= i.status;
			if (i.status & DC_NET_ERROR)
				fprintf(stderr, "websocket connection was closed by the remote host\n");
			else { /* commerce identify */
				if (i.pass->api_io.status & DC_MUST_FREE)
					free(i.pass->body);
				i.pass->api_io.status |= DC_MUST_FREE;
				i.pass->body_length = smprintf(&i.pass->body, DC_IDENTIFY_FORMAT, i.client->authorization, DC_INTENTS);
				lws_callback_on_writable(i.pass->wsi);
			}	
			dc_api_stack(i); /* cl.stat is either NET_ERROR 4 closed or error or OK 4 esta */
			break;
		case DC_API_REGISTER:
			break;
		case DC_API_STATUS:
			break;
		case DC_API_USER:
			break;
		case DC_API_ROLE:
			break;
		case DC_API_NONE:
			break;
		case DC_API_ATTACH:
			DC_MR(i.program->attached_functions); /* makes room for at least one */
			i.program->attached_functions[i.program->attached_functions_length++] = i.attached_function; /* is on heap */
			break;
	}
}
struct dc_api_io dc_api_o (struct dc_api_io i /* for ->program */) {
	if (i.program->lws_context)
		lws_service(i.program->lws_context, 0);
	struct dc_api_io o = {
		.type = DC_API_NONE,
		.program = i.program
	};
	/* dc_api_stack pop: */
	if (i.program->api_ios_length) {
		memcpy(&o, (i.program->api_ios[--i.program->api_ios_length]), sizeof(o));
		dc_api_io_free(i.program->api_ios[i.program->api_ios_length]);
	}
	int is_broken = 0;
	for (size_t j = 0; j < i.program->attached_functions_length; j++) { /* call attached functions */
		if (i.program->attached_functions[j]->type != DC_API_TIMEOUT) {
			if (i.program->attached_functions[j]->type == o.type && !is_broken)
				if (i.program->attached_functions[j]->function(o, i.program->attached_functions[j]->user_data) & DC_BREAK)
					is_broken++;
		} else
			if (i.program->attached_functions[j]->last + i.program->attached_functions[j]->every < time(NULL))
				if (!(i.program->attached_functions[j]->function(o, i.program->attached_functions[j]->user_data) & DC_RETRY))
					i.program->attached_functions[j]->last = time(NULL);
	}
	return o;
}