path: root/src/api.c

#define SC_CAPI(c, b, h, e, ...) sc_api(c, b, h, 0##__VA_OPT__(1), e __VA_OPT__(,) __VA_ARGS__)
#define SC_CAPIX(c, b, h, e, ...) sc_capix(c, b, h, 0##__VA_OPT__(1), e __VA_OPT__(,) __VA_ARGS__)
char * sc_api (struct sc_cache * c, char * body, char * headers, int isfmt, char * endpoint, ...) {
	if (!c || !endpoint)
		return NULL;
	size_t va_count = parse_printf_format(endpoint, 0, NULL);
	char * endpoint_formatted = NULL;
	long response_code = 0;
	if (isfmt && va_count > 0 && endpoint_formatted == NULL) {
		va_list ap, ap2;
		va_start(ap, endpoint);
		va_copy(ap2, ap);
		size_t strlenm = vsnprintf(NULL, 0, endpoint, ap);
		endpoint_formatted = malloc(sizeof(char)*strlenm+1);
		vsnprintf(endpoint_formatted, strlenm+1, endpoint, ap2);
		va_end(ap);
		va_end(ap2);
	}
	if (!headers)
		headers = "";
	char * hedrs = malloc(sizeof(char)*strlen(headers)+strlen(SC_HTTP_HEADERS)+1);
	strcpy(hedrs, SC_HTTP_HEADERS);
	strcat(hedrs, headers);
	char * contentType = NULL;
	char * redir = NULL;
	char * buf = malloc(sizeof(char)*SC_HTTP_RBUFSIZE);
	size_t buf_sizeof = SC_HTTP_RBUFSIZE;
	size_t buf_length = 0;
	int readstatus = 0;
	void * r = xmlNanoHTTPMethodRedir(
			endpoint_formatted ? endpoint_formatted : endpoint,
			body ? "POST" : "GET",
			body,
			&contentType,
			&redir,
			hedrs,
			body ? strlen(body) : 0
			);
	if (!r) {
		SC_LOG(SC_LOG_ERROR, c, "!r, endpoint: %s", endpoint_formatted ? endpoint_formatted : endpoint);
		goto rc;
	}
	response_code = xmlNanoHTTPReturnCode(r);
	if (!(response_code - 200 >= 0 && response_code - 200 < 100)) {
		SC_LOG(SC_LOG_ERROR, c, "response_code == %ld, endpoint: %s", response_code, endpoint_formatted ? endpoint_formatted:endpoint);
	}
	while ((readstatus = xmlNanoHTTPRead(r, buf+buf_length, buf_sizeof-buf_length)) > 0) {
		buf_length += readstatus;
		if (buf_sizeof-buf_length < SC_HTTP_RBUFSIZE) {
			buf_sizeof *= SC_REALLOC_K;
			buf = realloc(buf, sizeof(char)*buf_sizeof); /* this IS safe, no matter how hard valgrind complains */
		}
	}
	buf[buf_length++] = '\0';
	if (readstatus == -1)
		SC_LOG(SC_LOG_ERROR, c, "readstatus == -1, endpoint: %s", endpoint_formatted ? endpoint_formatted : endpoint);
	xmlNanoHTTPClose(r);
	SC_LOG(SC_LOG_DEBUG, c, "contentType = %s, redir = %s", contentType ? contentType : "NULL", redir ? redir : "NULL");
rc:
	free(endpoint_formatted);
	free(contentType);
	free(redir);
	free(hedrs);
	return buf;
}
htmlDocPtr sc_capix (struct sc_cache * c, char * body, char * headers, int isfmt, char * endpoint, ...) {
	if (!c || !endpoint)
		return NULL;
	size_t va_count = parse_printf_format(endpoint, 0, NULL);
	char * endpoint_formatted = NULL;
	if (isfmt && va_count > 0 && endpoint_formatted == NULL) {
		va_list ap, ap2;
		va_start(ap, endpoint);
		va_copy(ap2, ap);
		size_t strlenm = vsnprintf(NULL, 0, endpoint, ap);
		endpoint_formatted = malloc(sizeof(char)*strlenm+1);
		vsnprintf(endpoint_formatted, strlenm+1, endpoint, ap2);
		va_end(ap);
		va_end(ap2);
	}
	char * buf = sc_api(c, body, headers, 0, endpoint_formatted ? endpoint_formatted : endpoint);
	htmlDocPtr htmldoc = parseHtmlDocument(buf, endpoint_formatted ? endpoint_formatted : endpoint);
	free(buf);
	free(endpoint_formatted);
	return htmldoc;
}
char * sc_find_class (char * haystack, const char * definition) { /* you must free class after calling */
	if (!haystack || !definition)
		return NULL;
	char * class = strcasestr(haystack, definition);
	if (!class)
		return NULL;
	int found = 0;
	for (; class > haystack; class--)
		if (class[-1] == '.' && (found = 1))
			break;
	if (!found)
		return NULL;
	char * endofclass = class;
	found = 0;
	for (; *endofclass; endofclass++) /* google only has alphanumeric class names. TODO: be pedantic and conformic to w3 stds */
		if (!isalnum(endofclass[0]) && (found = 1))
			break;
	if (!found)
		return NULL;
	char * toreturn = malloc(endofclass-class+1);
	strncpy(toreturn, class, endofclass-class);
	toreturn[endofclass-class] = '\0';
	return toreturn;
}
int sc_fix_url (char ** h) { /* fixes a (result) URL in-place (removes tracking nonsense, so resulting URL is shorter or equl) */
	if (!h || !*h) /* stage 0: prevent accidental death */
		return -1;
	if (!strncmp(*h, "/url?q=", strlen("/url?q="))) { /* stage 1: url may be tracking url by google results */
		*h = *h+strlen("/url?q=");
		*strchrnul(*h, '&') = '\0';
		urldecode(*h, *h);
	}
	char * c = NULL;
	if ((c = strcasestr(*h, "googleweblight.com/fp?u="))) { /* stage 2: url may be "light web" tracking url by google results */
		*h = c+strlen("googleweblight.com/fp?u="); /* we could disable this with a cookie but meh, this is easier and _stateless_ */
		*strchrnul(*h, '&') = '\0';
		urldecode(*h, *h);
	} /* TODO: be pedantic and remove utm_source and other tracking bullshit */
	return 1;
}
enum sc_return sc_query_google (const char * s, /* breaking change: changed return type */
		struct sc_cache * c,
		struct sc_query * q,
		char ** redirect, /* variable redirect will be set to a heap allocated string that must be freed by the caller if the upstream returned results for a different query. in that case the returned query object will be for a different search string! -- if NULL, request that upstream does not enable "results for" feature */
		SC_OPT_TYPE opt) { /* check4cachedB4 */
	/* query is in most cases NULL. then it will be allocated and put into sc_cache. otherwise response will be put into passed q. */
	/* if query is not NULL, it MUST be initialized */
	/*
		remarks:
			* we are using wap.google.com over HTTP and with a user-agent string of a nokia mobile phone, so we get a lite website
			* we determine which class holds a specific value by looking at the css definitions
				- result title: the only class that has definition {color:#1967D2;font-size:14px;line-height:16px}
					+ A links have this class set, but they have a child SPAN element that then holds the text of the title
					+ A href points to a tracking relative link, starting with /url?q=. the q parameter contains the (obv urlencoded) link.
				- result date: class has only one definition, {color:#70757a}, but same definition has the class for the settings A link.
					+ extract those two classes and find the one that is only present on SPAN text elements.
				- result description: once we have the result div, the description is the //table//span with the appropriate class
					+ the appropriate class is the only one with {word-break:break-word}. note that this class also describes other elements.
				- result div: to get the result div, we need the parent of the parent of the A link of the title.
			* result dates are sometimes relative ("an hour ago") and heavily depend on the client location, based on IP.
				- we won't parse those yet
			* I couldn't find anything with ratings, so we won't parse thouse either yet
			* captcha: google knows that this nokia phone we're pretending to be doesn't support javascript, but does not care, and loads an obfuscated captcha anyways that would be hard to defeat for now without some kind of chromium emulation we really don't want.
	*/
	enum sc_return rs = 1;
	char * xpath = NULL;
	char * descclass = NULL;
	char * titleclass = NULL;
	char * imageclass = NULL;
	char * resultsforclass = NULL;
	char * xpathsugg = NULL;
	htmlDocPtr xmldoc = NULL;
	char * txtdoc = NULL;
	int qwasgiven = 0;
	SC_LOG(SC_LOG_DEBUG, c, "%s called, redirect is %p", __func__, redirect);
	if (redirect)
		*redirect = NULL;
	if (!s || !c) {
		rs = SC_BADCALL;
		goto rc;
	}
	int sl = strlen(s);
	if (!q)
		q = sc_query_init();
	else
		qwasgiven++;
	char * us = malloc(sizeof(char)*strlen(s)*3+1);
	urlencode(us, s);
	txtdoc = SC_CAPI(c, NULL, NULL, "http://wap.google.com/search?q=%s&num=100&ie=UTF-8%s%s", us, (opt&SC_OPT_IMAGE) ? "&tbm=isch" : "", redirect ? "" : "&nfpr=1");
	// fprintf(stdout, "%s\n", txtdoc);
	free(us);
	if (!txtdoc) {
		SC_LOG(SC_LOG_ERROR, c, "!txtdoc");
		rs = SC_EMPTYRESPONSE;
		goto rc;
	}
	if (strstr(txtdoc, "In the meantime, solving the above CAPTCHA will let you continue")) {
		rs = SC_CAPTCHA;
		goto rc;
	}
	resultsforclass = sc_find_class(txtdoc, "{color:#1967d2}");
	if (opt & SC_OPT_IMAGE) {
		imageclass = sc_find_class(txtdoc, "{font-family:Roboto,Helvetica,Arial,sans-serif}");
		if (!imageclass) {
			SC_LOG(SC_LOG_ERROR, c, "!imageclass, txtdoc = %s", txtdoc);
			rs = SC_NOIMGCLASS;
			goto rc;
		}
	} else {
		titleclass = sc_find_class(txtdoc, "{color:#1967D2;font-size:14px;line-height:16px}");
		descclass = sc_find_class(txtdoc, "{word-break:break-word}");
		if (!titleclass || !descclass) {
			SC_LOG(SC_LOG_ERROR, c, "!titleclass || !descclass, txtdoc = %s", txtdoc);
			rs = SC_NOCLASS;
			goto rc;
		}
	}
#define SC_GTXF "/html/body//a[contains(@class, '%s')]" /* result a */
#define SC_GTXD /* description */ "../..//table//span[@class='%s']"
#define SC_GTXB /* breadcrumbs */ ".//span[@class='%s']"
#define SC_GTXI "//div[@class='%s']//a"
#define SC_GTR q->results[q->results_length-1]
	xpath = malloc(strlen((opt & SC_OPT_IMAGE) ? imageclass : titleclass)+strlen((opt & SC_OPT_IMAGE) ? SC_GTXI : SC_GTXF));
	sprintf(xpath, (opt & SC_OPT_IMAGE) ? SC_GTXI : SC_GTXF, (opt & SC_OPT_IMAGE) ? imageclass : titleclass);
	xmldoc = parseHtmlDocument(txtdoc, NULL);
	if (qwasgiven) /* as you can see, when q is given, queries will be write-locked for the whole XML processing time! */
		SC_CWLE(c, c->queries_lock);
	q->results_length = 0;
	gnu_code_start;
	void sc_query_google_eachnode (xmlNodePtr node, void * data) {
		if (node->type == XML_ELEMENT_NODE) {
			xmlAttrPtr href = xmlHasProp(node, BAD_CAST "href");
			if (href) {
				char * hreflink = (char *) xmlGetProp(node, BAD_CAST "href"); /* xmlGetProp copies and allocates */
				if (!hreflink) {
					SC_LOG(SC_LOG_ERROR, c, "!hreflink");
					rs = SC_NOHREF;
					return;
				}
				if (opt & SC_OPT_IMAGE) {
					char * imgurl = NULL; /* do not free those when allocated by sscanf, as they will directly go into the struct. */
					char * imgrefurl = NULL; /* easy, huh? */
					SC_LOG(SC_LOG_DEBUG, c, "hreflink = %s", hreflink);
					sscanf(hreflink, "/imgres?imgurl=%m[^&]&imgrefurl=%m[^&]", &imgurl, &imgrefurl);
					xmlFree(hreflink);
					if (!imgurl && !imgrefurl) {
						SC_LOG(SC_LOG_ERROR, c, "!imgurl && !imgrefurl, txtdoc = %s", txtdoc);
						/* rs = -7; */ /* we continue running not fail because of a single picture */
						free(imgurl);
						free(imgrefurl);
						return; /* check! */
					}
					urldecode(imgurl, imgurl);
					urldecode(imgrefurl, imgrefurl);
					if (q->results_sizeof <= q->results_length)
						SC_BIGGER_ARRAY(q->results, sc_result, 1);
					q->results_length++;
					SC_GTR->query = q;
					SC_GTR->title = NULL; /* can't get title from here, would have to load /imgres, which is bloat */
					SC_GTR->url = imgrefurl;
					SC_GTR->desc = imgurl;
					SC_GTR->breadcrumbs = NULL;
				} else {
					char * orig_hreflink_for_free = hreflink;
					sc_fix_url(&hreflink);
					char * x = malloc(strlen(descclass)+strlen(SC_GTXD));
					char * xbread = malloc(strlen(descclass)+strlen(SC_GTXB));
					sprintf(x, SC_GTXD, descclass /* remember, kids, GNU C is fucking legendary */);
					sprintf(xbread, SC_GTXB, descclass /* remember, kids, GNU C is fucking legendary */);
					xmlNodePtr descnode = nthNodeXN(node, x, 0);
					if (!descnode) /* description may be above, see https://support.google.com/websearch?p=featured_snippets */
						descnode = nthNodeXN(node, "../../div/div", 0);
					xmlNodePtr breadnode = nthNodeXN(node, xbread, 0);
					free(x);
					free(xbread);
					if (q->results_sizeof <= q->results_length)
						SC_BIGGER_ARRAY(q->results, sc_result, 1);
					q->results_length++;
					SC_GTR->query = q;
					char * cp = (char *) xmlNodeGetContent(node->children);
					if (cp) {
						SC_GTR->title = malloc(strlen(cp)+1);
						strcpy(SC_GTR->title, cp);
						xmlFree(cp);
					} else SC_GTR->title = NULL;
					if (hreflink) {
						SC_GTR->url = malloc(strlen(hreflink)+1);
						strcpy(SC_GTR->url, hreflink);
					} else SC_GTR->url = NULL;
					if (orig_hreflink_for_free)
						xmlFree(orig_hreflink_for_free);
					cp = (char *) xmlNodeGetContent(descnode);
					if (cp) {
						SC_GTR->desc = malloc(strlen(cp)+1);
						strcpy(SC_GTR->desc, cp);
						xmlFree(cp);
					} else SC_GTR->desc = NULL;
					cp = (char *) xmlNodeGetContent(breadnode);
					if (cp) {
						SC_GTR->breadcrumbs = malloc(strlen(cp)+1);
						strcpy(SC_GTR->breadcrumbs, cp);
						xmlFree(cp);
					}
				}
			}
		}
	}
	eachNodeX(xmldoc, xpath, sc_query_google_eachnode, NULL);
	gnu_code_end;
	if (rs < 0) {
		SC_LOG(SC_LOG_ERROR, c, "rs < 0 (rs == %d)", rs);
		if (qwasgiven)
			SC_CUE(c, c->queries_lock);
		goto rc;
	}
	q->string = realloc(q->string, sl+1);
	strcpy(q->string, s);
	if (resultsforclass) {
		xpathsugg = malloc(512+strlen(resultsforclass));
		sprintf(xpathsugg, "//a[contains(@class, '%s')]", resultsforclass);
		xmlNodePtr suggnode = nthNodeX(xmldoc, xpathsugg, 0);
		if (suggnode && xmlHasProp(suggnode, BAD_CAST "href")) {
			char * href = (char *) xmlGetProp(suggnode, BAD_CAST "href");
			char * content = (char *) xmlNodeGetContent(suggnode);
			if (href && strstr(href, "&spell=1&"))
				strcpy((q->suggested = realloc(q->suggested, strlen(content)+1)), content);
			xmlFree(href);
			xmlFree(content);
		} else {
			free(q->suggested);
			q->suggested = NULL;
		}
	} else {
		free(q->suggested);
		q->suggested = NULL;
	}
	xmlNodePtr first = nthNodeX(xmldoc, xpathsugg, 1);
	if (redirect && xpathsugg && q->suggested && xmlHasProp(first, BAD_CAST "href")) {
		char * href = (char *) xmlGetProp(first, BAD_CAST "href");
		if (href && strstr(href, "&nfpr=1&")) {
			*redirect = q->suggested;
			q->suggested = NULL;
			q->string = realloc(q->string, strlen(*redirect)+1);
			strcpy(q->string, *redirect);
		}
		xmlFree(href);
	}
	q->cache = c;
	q->lookup_time = time(NULL);
	q->opt |= opt | SC_ENGINE_GOOGLE;
	if (!qwasgiven) {
		SC_CWLE(c, c->queries_lock);
#ifdef SC_OLD_STORAGE
		if (c->queries_sizeof <= c->queries_length)
			SC_BIGGER_ARRAY(c->queries, sc_query, 0);
		c->queries_length++;
#define SC_GTQ c->queries[c->queries_length-1]
		SC_GTQ = q;
#else /* we don't detect here if query is already stored, but it should not be ... */
		tsearch(q, &c->qrp, SC_COMPAR_CAST sc_query_compar);
#endif
	}
	SC_CUE(c, c->queries_lock);
rc:
	if (!qwasgiven && rs < 0)
		sc_query_free(q);
	xmlFreeDoc(xmldoc);
	free(txtdoc);
	free(titleclass);
	free(descclass);
	free(imageclass);
	free(resultsforclass);
	free(xpath);
	free(xpathsugg);
	return rs;
}