Possible new feature for book details

[chaley]

I am considering adding the ability to display the output of templates in the comments section of book details. The output can go at the top or at the bottom.

Rationale: there are times when one wants to display something more complicated without creating a composite column for it. The template could generate arbitrary html, combine columns together, or both. Examples: tables of links to other books, text from multiple columns combined into a single display, books in a series sorted by %read, and so on.

The rationale is similar to why I added template searches -- permitting complex searches without requiring making a dedicated column.

The question: is this something people would use? No reason to build and maintain it if not.

[ownedbycats]

This is something I think I could use.

Example: I have a composite taglike called #links to display links using urls_from_identifiers. As this is only intended for the Book Details and not for sorting/displaying in the list, it makes sense to move it over.

Originally Posted by chaley

The rationale is similar to why I added template searches -- permitting complex searches without requiring making a dedicated column.

This also made me wonder if the columns I use only for sorting books in a specific way via View Manager could somehow be deprecated as well.

Example: The composite #onreadinglist lets me sort the series-like #readinglist to the top without reversing the series order.

[capink]

I would like to have this feature as well. I actually has a composite column only for this purpose (displaying only in books details). I would imagine this feature will improve performance.

[chaley]

The lack of demand tells me that this isn't something I should build, at least as described. This is expecially true given you can get the same behavior by creating a composite column, hiding it in the book view, and using the new "Show with comments in book details" option.

However, I am considering an alternate approach: providing a way to register a "generator function" for a composite column. If this works out then when the value of a composite column is required, calibre calls the generator function instead of calling the template processor. The generator must return a string matching the composite column type definition: date, number, or text. If text then it can be HTML, markdown, or plain text.

This scheme allows a plugin to do more-or-less arbitrary computations to produce the column value. For example, it could display:

• an HTML table of links for the book.
• bibliographic information about the authors
• timelines for series
• information about book editions
• formatted bookmarks
• ...

Because these are normal composites they would work in search and sort, as well as be displayable in book details. They could be displayed in the book list if the callback is fast enough.

[ownedbycats]

I'm afraid I don't really understand. do you have an example of how this would differ from a regular composite column?

[chaley]

Originally Posted by ownedbycats

I'm afraid I don't really understand. do you have an example of how this would differ from a regular composite column?

The generator function can do things that a template can't, or at least shouldn't. For example, it can keep information in the calibre database and produce images.

Some examples:

1) An "author information" plugin. This plugin would store information about an author such as descriptive text, pen names, pictures, location, languages, book lists, what-have-you. The plugin would register itself as a generator function, which would be called when book details is displayed. The plugin would build HTML of the information based on the current book using authors or some other column, which book details would display.

2) Should DaltonST choose, he could display the output of the Notes Viewer in book details. His plugin would be called when details for a book are displayed. It would return the HTML interpretation of the note that it currently generated. His Entity Manager might have similar possibilities.

3) A "series" plugin that returns information about the current series, for example text that describes the universe, offshoot series, reading order, and the like.

4) A plugin that generates a graph of book ratings with the current book highlighted. The graph could be by genre, series, author, library, or what-have-you.

[ownedbycats]

That can be useful

[Wiggo]

Originally Posted by chaley

Some examples:

1) An "author information" plugin. This plugin would store information about an author such as descriptive text, pen names, pictures, location, languages, book lists, what-have-you. The plugin would register itself as a generator function, which would be called when book details is displayed. The plugin would build HTML of the information based on the current book using authors or some other column, which book details would display.

[...]

3) A "series" plugin that returns information about the current series, for example text that describes the universe, offshoot series, reading order, and the like.

1. So I enter all data in this generator/PI and it will be displayed in book details?
2. No need of custom columns and composite columns for this kind of info anymore?
3. It's searchable?
4. It's sortable? I don't think so

My main focus would be pen-names, related books and series.

If that were possible without a big template thing, I would be very pleased. My calibre has already become noticeably slower in the meantime

[chaley]

Originally Posted by Wiggo

1. So I enter all data in this generator/PI and it will be displayed in book details?
2. No need of custom columns and composite columns for this kind of info anymore?
3. It's searchable?
4. It's sortable? I don't think so

My main focus would be pen-names, related books and series.

If that were possible without a big template thing, I would be very pleased. My calibre has already become noticeably slower in the meantime

I can't control what a "generator" plugin will do. I don't intend to write such a plugin. Also note that there is no guarantee that a generator will be fast. It could slow down the display of book details if, for example, it does web queries to generate the displayed information.

As for no need for other custom columns, that depends on what you use them for. Perhaps some eventual plugin can replace them -- I can't say.

The generator plugin will have the option of providing searchable text. However, like all searches this will find books, not (for example) series information. The plugin can provide its own interface to search the series info.

It isn't clear to me what it means to sort by the generated text. It might be meaningless given that "sort" works on the booklist, not the stored series information.

[ownedbycats]

Do you have any examples of a generator function that a user can setup without someone first making a custom plugin?

[chaley]

Originally Posted by ownedbycats

Do you have any examples of a generator function that a user can setup without someone first making a custom plugin?

No I don't. The generator must work in some semantic domain and use/control data related to that domain. If it doesn't then they are no different from bog-standard templates.

[BetterRed]

Could a generator plugin access a library other than the current library.

Example: glean content from my Books library to be shown in the Book Details of my Comics Library?

BR

[chaley]

Originally Posted by BetterRed

Could a generator plugin access a library other than the current library.

Example: glean content from my Books library to be shown in the Book Details of my Comics Library?

BR

Yes, but performance could be an issue. Opening another library in order to display book details could be unacceptably slow. I don't know. A "performance problem" could be mitigated with caching, for example if the timestamp on the "other" metadata.db hasn't changed, but I can't say if this makes sense in the context you are envisioning.

What I need, really, is someone who is interested in making a generator plugin (almost certainly a User Interface Plugin that registers a generator function), so we can work out exactly how (and whether) it would work.

[capink]

Originally Posted by chaley

What I need, really, is someone who is interested in making a generator plugin (almost certainly a User Interface Plugin that registers a generator function), so we can work out exactly how (and whether) it would work.

Does this have to be a dedicated plugin, or can it be done from and existing plugin e.g. writing custom or builtin actions for Action Chains.

I can make the plugin call the actions to register the generator functions. if possible, would it need a restart whenever a custom action is added through the module editor?

[chaley]

Originally Posted by capink

Does this have to be a dedicated plugin, or can it be done from and existing plugin e.g. writing custom or builtin actions for Action Chains.

I am thinking that it would be done in interface plugins by registering a function to be a generator for a lookup key.

I can make the plugin call the actions to register the generator functions. if possible, would it need a restart whenever a custom action is added through the module editor?

I don't see a need to restart. A second call to the registration function would override the first. If the registration function no longer exists then "normal" processing would happen.

However, this does point out the need to be able to unregister a generator.

I am going to think about this a bit while looking at this. The idea might be an elegant solution to something I have thought about for months -- how to provide meta information about books such as author biographies and the like.