Friday, May 10, 2013

Licence Changed

Recently I'm changing the license of pdf2htmlEX, but most of you should not be worried.

As you know pdf2htmlEX is released under GPLv2 or GPLv3, with a few files released under the MIT License. GPL does not protect the source code for usage in online services, as AGPL does.

I don't think it would be necessary to apply AGPL, since a wise service provider should have realized that making their modifications public is an advantage to themselves, and indeed I've received serveral patches from service providers.

Unlike most GPL softwares, pdf2htmlEX is designed for service providers. I expect the common use to be customization for different services instead of redistributions. But I don't want it to end up with lots of wrappers without any feedback. So in order to let more people know about this technology, and to attract more feedbacks, recently I added a new term in the license:

If you want to use pdf2htmlEX (or your modified version) in your online service,
through which a user can provide one or more files through a computer network,
and view any part of the result produced by pdf2htmlEX (or your modified version) on the file(s) provided by the user, you should credit pdf2htmlEX with a proper link to in the page where the result is presented, or the homepage of your service, or a page directly accessible from the homepage of your service.
Any derivate works should also include this term.
For example, you should credit pdf2htlmEX if pdf2htmlEX (or your modified version) must be called after a user upload some files and before the user can see the result of the files, you should credit pdf2htmlEX.

Here are a few explanations:
This term applies if your service involves "online conversion", which means the services allow users to upload files and view the conversion by pdf2htmlEX (or your modification). This terms do not apply if you convert documents of your own and present them online -- but still you are encouraged to credit pdf2htmlEX.

Three locations are mentioned in the term:
  1. The page where you present the converted document
  2. The homepage
  3. A page directly accesible from the homepage
The first two should be intuitive. But I may want a clean homepage if I were the UI designer, and I do not want to see the ugly logo of those document-embedding plugins, therefore I stated the 3rd one. I expect it to be the About page, the Acknowledgement page, or a page where you list technogies used in your service.

If you have done this, you are encouraged to send me the name of your service and a url to where pdf2htmlEX is creditted. This is for the purpose of statistics, and in the future I may create a list of 'sites that use pdf2htmlEX'.

I'm not a lawyer, and I don't know how this is achieved in other softwares. I just want to express my thoughts in this term, hopefully which is clearly explained in this post.

Please tell me what do you think about this additional term!


  1. Is it possible to buy a different licence from you?

    We are using this as an internal system but still web based, where documents are converted, other stuff happens, person sees the pdf (as html), other things happen, then they move on.

    Because this isn't an online service, do we still need to have a link to your github page?

    1. It depends. If the person/group who views the document is the same person/group who provides the system, then pdf2htmlEX may be viewed as offline usage. Otherwise you need to attribute pdf2htmlEX.

      But if you use pdf2htmlEX internally, why does it bother you to attribute it?

  2. If I wanted to distribute this in a closed source commercial application, could I purchase a non-GPL license, and if so, how much would it cost?