How to find out what page number was loaded during pdf rendering with reportlab

Question

How to determine which page (page number is needed) will each stream after rendering in pdf. I was thinking of adding a user id attribute to the current one, so I will know that it is fluid. But how can I determine which page it will be placed on? What is the best way to achieve this?

Answer 1

I ended up with the following solution. Added custom id flo_id for each thread. And override the handle_flowable method in BaseDocTemplate, where the id was checked and stored,

class SignDocTemplate(BaseDocTemplate): blocks_to_pages = {} def handle_flowable(self, flowables): f = flowables[0] BaseDocTemplate.handle_flowable(self, flowables) if hasattr(f,'flo_id'): if self.blocks_to_pages.has_key(self.canv._pageNumber): self.blocks_to_pages[self.canv._pageNumber].append(f.flo_id) else: self.blocks_to_pages[self.canv._pageNumber]= [f.flo_id,] 

And after creating the document, it will be available in the document instance in the variable blocks_to_pages.

Answer 2

At what point do you need this information? It becomes available as the document is created, so you can get it after rendering using overriding methods like afterPage , afterDrawPage and afterFlowable . Then you can get the page number from the DocTemplate class (I believe the class variable is called something like _currentPage , but you need to check the ReportLab code, since I don't think this is documented).