Using Ruby, What Is the Most Efficient Way to Get the Content Type of a Given Url

Using Ruby, what is the most efficient way to get the content type of a given URL?

This is what I'd do if I want simple code:

require 'open-uri'
str = open('http://example.com')
str.content_type #=> "text/html"

The big advantage is it follows redirects.

If you're checking a bunch of URLs you might want to call close on the handles after you've found what you want.

How to get content type of a given url inside Javascript?

Atlast I could figure out the whole thing with the great help of @Ian. Here is my completed code : In javascript file :

    $("#wiki_form_url").change(function () {
        $.ajax({
            type: "GET",
            url: "/wiki_forms/content",
            data: {
                input_url: $("#wiki_form_url").val()
            },
            dataType: "text"
        }).done(function (data) {
                    // `data` contains the content-type
                    alert('Success');
                    console.log(data);
//                    alert(data);
                }).fail(function () {
                    alert("failed AJAX call");
                });
    });

Inside my wiki_forms controller I created a new method named content :

  def content 
    req = open(params[:input_url])
    render :text => req.content_type 
  end

Then added a new route in routes.rb file :

  get "/wiki_forms/content" => 'wiki_forms#content'

and used /wiki_forms/content as the ajax request url. And, everything is working nicely now.

Get Content Type of Request

I would usually go for request.format and request.content_type for reading these header fields.

EDIT: found a bit more on this that might help: https://stackoverflow.com/a/1595453/624590

How can I get content type from an ActiveStorage attachment?

Yes, there is a shorter solution: @video.source_blob.content_type.

I recommend you to look at the source code of ActiveStorage, there you can see all the available methods and possibilities that are not always well documented.

How to send url-encoded form data using Faraday's post method?

The issue is that the parameters should start with capital letters. Your Faraday request is otherwise correct, but your form_data method should look like:

  def form_data
    {
      From: "whatsapp:+5491112312312",
      Body: "Hello. Your order is on the way",
      To: "whatsapp:+541132132121",
    }
  end

Verifying a remote image is actually an image file in ruby?

I would check to see if the service returns the proper mime types in the Content-Type HTTP header. (here's a list of mime types)

For example, the Content-Type of the StackOverflow homepage is text/html; charset=utf-8, and the Content-Type of your gravatar image is image/png

To check the Content-Type header for image in ruby using Net::HTTP, you would use the following:

def remote_file_exists?(url)
    url = URI.parse(url)
    Net::HTTP.start(url.host, url.port) do |http|
      return http.head(url.request_uri)['Content-Type'].start_with? 'image'
    end
end

Is it possible to download files from Filetype fields using Ruby?

Since you didn't give a valid URL, it's difficult to test solutions for you.

In general, retrieving the content of a URL is the same, whether it's a page or a file. Ruby's built-in OpenURI is the fast path:

require 'open-uri'
file = open('http://example.com').read

Saving that file is easy:

IO.binwrite('/path/to/file_to_save', file)

Using binwrite avoids any line-end translations that would occur saving binary data. For text data use:

IO.write('/path/to/file_to_save', file)

Both IO.binwrite and IO.write are documented in the IO module.

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