Multipart support

[kawakami-o3]

Do you have any plan to support a multipart POST request?
I will code this feature later.

[asciimoo]

@kawakami-o3 this is definitely a missing and useful feature. I'd appreciate if you could implement it.

[vosmith]

So I started working on this and gave it a good try. The main issue that there is no way to set custom headers.

Right now all POST requests are forced into the content-type application/x-www-form-urlencoded.

I tried creating new functions like

func (c *Collector) PostMultipart ...

But once it hits scrape, the content gets set. I also tried adding an onRequest callback method to set the header, but then this callback affects all successive requests once it becomes a part of the callback stack.

Frankly I found it difficult to accomplish this without significant changes to how the headers are handled.

[asciimoo]

So I started working on this and gave it a good try.

Awesome! =)

Right now all POST requests are forced into the content-type application/x-www-form-urlencoded

What about adding a new "Content-Type" string parameter to scrape() function and in case it is not empty we set the content type to that?

[vosmith]

Sounds like it should work! I'll go ahead and give it a try👍🏾

[kawakami-o3]

I am late...
I planed to add a request data handler instead of requestData map[string]string.
If the handler contains a file, it can decide correct Content-Type.

Should I stop my work?

[asciimoo]

@kawakami-o3 seems like @vosmith nearly finished the implementation. Let's wait for his solution to avoid duplicated work. What do you think?

[kawakami-o3]

I follow you.

[asciimoo]

added in 30e15f6 thank you for your work.