Clickable Book IDs on Book details pane

[Wiggo]

Originally Posted by chaley

Enhancement: the template could verify that the id actually exists, which can happen because of an input error or deleting a book. If the id doesn't exist then a message is displayed. Something like this:

program:
	j = '';
	for id in $#mytextmult:
		if j then j = j & ', ' fi;
		id_exists = book_count('id:' & id, 0);
		if id_exists != 1 then
			j = j & 'No such id ' & id
		else
			j = j & '<a href="' & 'calibre://show-book/_hex_-' &
				to_hex(current_library_name()) & '/' & id & '">' & id & '</a>'
		fi
	rof

which produces this:
Attachment 196676

Hi chaley

I get this error

VORLAGENFEHLER The book_count() function cannot be used in a composite column

Any idea?

Thank you!

[chaley]

Originally Posted by Wiggo

Hi chaley

I get this error

[CODE]VORLAGENFEHLER The book_count() function cannot be used in a composite column

Any idea?

Thank you!

The template database functions can be very slow. To avoid surprises and bug reports, I decided the user must specifically allow them, so the person can see the difference in performance.

See Preferences / Tweaks / Allow template database functions in composite columns (ID: allow_template_database_functions_in_composites)

[Wiggo]

[Wiggo]

Is there a possibility that the links also works "ouside" of the current view?
If the book is not listed in the view, the linking doesn't work

Edit: re-read the manual - not possible

[chaley]

Originally Posted by Wiggo

Is there a possibility that the links also works "ouside" of the current view?
If the book is not listed in the view, the linking doesn't work

Edit: re-read the manual - not possible

Why not? The documentation says that if the book isn't in the current VL then the VL is cleared. If specify a VL and the book isn't in that VL then the VL is ignored.

[Wiggo]

hmm.. you're right. I should concentrate again more while reading.

Anyhow. I don't use VLs.
When I search for "same author" then clicking on a related link doesn't lead to the book of a different author. But if I create a VL from the search, then it works.

[chaley]

I understand what is happening. Finding similar authors does a search. That search is still in effect when you click the link, and it is applied to the results. If the book "selected" by clicking the link doesn't match the search then it isn't shown.

It isn't clear to me that a show_book link should preserve/honor the search, but that is a different question.

There are two solutions:

• Force the "click" to clear the search by specifying a non-existent VL. This will of course clear any VL as well. This template (python) does that.
  

  python:
  def evaluate(book, context):
  	cache = context.db.new_api
  	ids = book.get('#mytextmult', [])
  	answer = []
  	for id_ in ids:
  		if cache.has_id(int(id_)):
  			answer.append(f'<a href="calibre://show-book/_/{id_}?virtual_library=+@+@">{id_}</a>')
  		else:
  			answer.append(f"Book id {id_} doesn't exist")
  	return ', '.join(answer)

• Use a search link instead of a show link.
  

  python:
  def evaluate(book, context):
  	cache = context.db.new_api
  	ids = book.get('#mytextmult', [])
  	answer = []
  	for id_ in ids:
  		if cache.has_id(int(id_)):
  			answer.append(f'<a href="calibre://search/_?q=id:={id_}">{id_}</a>')
  		else:
  			answer.append(f"Book id {id_} doesn't exist")
  	return ', '.join(answer)

As before, you must change the name #mytextmult to match your column lookup name.

Python templates don't require the tweak.

[chaley]

Originally Posted by chaley

It isn't clear to me that a show_book link should preserve/honor the search, but that is a different question.

Kovid accepted a fix. If the target book is not in the search results then the search is cleared. Then if the target book is not in the VL the the VL is cleared.

The original template works with these changes, which are now in calibre source.

[Wiggo]

Thank you so much chaley!

Is there any difference in terms of e.g. perfomance between the 3?
Which one would you choose?

Edit: ahh, with python the view is always cleared.

[chaley]

Originally Posted by Wiggo

Is there any difference in terms of e.g. perfomance between the 3?
Which one would you choose?

The Python templates are *much* faster than the GPM templates. I would pick one of them. However, that might affect how you can maintain them.

Edit: ahh, with python the view is always cleared.

The templates I provided don't take into consideration the fix I made (in source but not released). They both will clear a virtual library. The search version shows only the requested book (the result of the search).

Given my fix, I would use a modified version of the first template that generates show-book links. It is functionally equivalent to the original GPM template, including not clearing searches, but much faster.

python:
def evaluate(book, context):
	cache = context.db.new_api
	ids = book.get('#mytextmult', [])
	answer = []
	for id_ in ids:
		if cache.has_id(int(id_)):
			answer.append(f'<a href="calibre://show-book/_/{id_}">{id_}</a>')
		else:
			answer.append(f"Book id {id_} doesn't exist")
	return ', '.join(answer)

[Wiggo]

Thanks again!

I will wait for the next release and try this modified python one.