How to Validate HTML Files using C/C++

If you’re looking for an easy way to identify invalid HTML files, the below code provides a simple and easy solution.

You can use these ready-to-run examples to call a free HTML file validation API: this service not only performs in-depth content verification, but it additionally calls out password-protection measures on the document (if applicable) and identifies any errors and warnings associated with the file.

You can begin structuring your API call by first installing Libcurl in your project:

libcurl/7.75.0

And then you can include the below examples in your file & authorize your requests with a free-tier API key:

CURL *curl;
CURLcode res;
curl = curl_easy_init();
if(curl) {
     curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "POST");
     curl_easy_setopt(curl, CURLOPT_URL, "https://api.cloudmersive.com/convert/validate/html");
     curl_easy_setopt(curl, CURLOPT_FOLLOWLOCATION, 1L);
     curl_easy_setopt(curl, CURLOPT_DEFAULT_PROTOCOL, "https");
     struct curl_slist *headers = NULL;
     headers = curl_slist_append(headers, "Content-Type: multipart/form-data");
     headers = curl_slist_append(headers, "Apikey: YOUR-API-KEY-HERE");
     curl_easy_setopt(curl, CURLOPT_HTTPHEADER, headers);
     curl_mime *mime;
     curl_mimepart *part;
     mime = curl_mime_init(curl);
     part = curl_mime_addpart(mime);
     curl_mime_name(part, "inputFile");
     curl_mime_filedata(part, "/path/to/file");
     curl_easy_setopt(curl, CURLOPT_MIMEPOST, mime);
     res = curl_easy_perform(curl);
     curl_mime_free(mime);
}
curl_easy_cleanup(curl);

That’s all the code you’ll need — now you can validate HTML files with ease.