CLI: calibredb add_custom_column

[ilovejedd]

Tried looking through the manual and searching the forums but wasn't able to find the info I needed.

1. Is it possible to use calibredb add_custom_column command line for creating composite columns with the template already populated? So far, I've only been able to use it for creating composite columns with an empty template.

2. How do I use the --display option for formatting dates? (e.g. MM/dd/yy: 12/31/12)

Thank you very much in advance!

[kovidgoyal]

IIRC it isn't possible, but chaley is the one who can give you a definitive answer.

[chaley]

The template goes into the display variable, which is JSON encoded. You can see what it should be by looking at the OPF for a book in your library. One example is

{"composite_template": "{:'approximate_formats()'}", 
"contains_html": false, 
"make_category": true, 
"composite_sort": "text"
}

I strongly recommend that you look at the OPF because there are several fields that can play a role.

Regarding date formatting, this is also a JSON-encoded string. One example is

{ "date_format": "yyyy/MM/dd" }

[kovidgoyal]

@chaley: Maybe we should add some examples to the documentation of that command, or at least a line telling the user to look at OPF files.

[ilovejedd]

Originally Posted by chaley

The template goes into the display variable, which is JSON encoded. You can see what it should be by looking at the OPF for a book in your library. One example is

{"composite_template": "{:'approximate_formats()'}", 
"contains_html": false, 
"make_category": true, 
"composite_sort": "text"
}

I strongly recommend that you look at the OPF because there are several fields that can play a role.

Yeah, I've actually looked through the OPFs and created copies of custom columns reformatted to be human legible (" to " then prettied up the resulting JSON with Notepad++). Still trying to get the date format right before I try anything more complex.

Originally Posted by chaley

Regarding date formatting, this is also a JSON-encoded string. One example is

{ "date_format": "yyyy/MM/dd" }

This, I've actually kinda tried (on Windows XP CLI). I believe I used the following:

--display='{"date_format":"MM/dd/yy"}'

Will have to double-check the actual batch file I used when I get home but I remember getting a message saying "No JSON object found" or something. For some reason, the batch file automatically terminates in XP (even though I explicitly added pause) so it's difficult to get the complete error message.

Edit:
I believe calibredb custom_columns -d would also show the basic JSON structure. Shows everything in single-quotes, though, but easy enough to figure out which needs to be converted to double-quotes.

[ilovejedd]

Since I'm working on Windows 7 right now, tried to see if I can get the full error message.

CLI:

calibredb add_custom_column --display '{"date_format":"MM/dd/yy"}' updated Updated datetime --with-library="Z:\library\fanfic"

Error Message:

Python function terminated unexpectedly
  No JSON object could be decoded (Error Code: 1)
Traceback (most recent call last):
  File "site.py", line 132, in main
  File "site.py", line 109, in run_entry_point
  File "site-packages\calibre\library\cli.py", line 1363, in main
  File "site-packages\calibre\library\cli.py", line 709, in command_add_custom_column
  File "json\__init__.py", line 326, in loads
  File "json\decoder.py", line 366, in decode
  File "json\decoder.py", line 384, in raw_decode
ValueError: No JSON object could be decoded

[chaley]

Apparently the Win7 CLI does not strip single quotes from arguments, making the JSON string invalid. The following works.

--display="{\"date_format\":\"MM/dd/yy\"}"

while this doesn't:

--display='{\"date_format\":\"MM/dd/yy\"}'

Putting print statements in the code, we see that the first arrives in calibre as

{"date_format":"MM/dd/yy"}

while the second second arrives as

'{"date_format":"MM/dd/yy"}'

(note the single quotes).

So, the solution for Win7 is to use double quotes and escape all internal quotes.

[chaley]

Originally Posted by kovidgoyal

@chaley: Maybe we should add some examples to the documentation of that command, or at least a line telling the user to look at OPF files.

Pushed changes:
- list the valid display dict keys by datatype
- point toward the OPF to get examples

[ilovejedd]

Originally Posted by chaley

Apparently the Win7 CLI does not strip single quotes from arguments, making the JSON string invalid. The following works.

--display="{\"date_format\":\"MM/dd/yy\"}"

while this doesn't:

--display='{\"date_format\":\"MM/dd/yy\"}'

So, the solution for Win7 is to use double quotes and escape all internal quotes.

Cool, that works great. Thanks! Might want to add this bit of info to the documentation. By the way, same issue exists and solution works with Windows XP. Alas, I've just never been able to capture the whole error message in XP as the batch file terminates directly after the first calibredb run (known issue, problem with Windows XP so can't fix so I just use the start workaround).

Funnily enough, I tried:

--display="{'date_format':'MM/dd/yy'}"

and:

--display='{\"date_format\":\"MM/dd/yy\"}'

I thought I had also tried:

--display="{\"date_format\":\"MM/dd/yy\"}"

but apparently not.