Preprocessor for mdbook to generate blockdiag.

mdbook-blockdiag.py

# Preprocessor for mdbook to generate blockdiag.
# By [email protected], MIT License
#
# Convert the following code in .md to svg:
#
#     ```
#     seqdiag {
#         A --> B
#         B --> C
#     }
#     ```
#
# Support actdiag, blockdiag, nwdiag, packetdiag, rackdiag and seqdiag. More examples: http://blockdiag.com/
#
# Add the following lines in book.toml to use it:
#
#     [preprocessor.blockdiag]
#     command = "python mdbook-blockdiag.py"
#     renderer = ["html"]

import datetime
import json
import os
import re
import sys

import actdiag.parser, actdiag.builder, actdiag.drawer
import blockdiag.parser, blockdiag.builder, blockdiag.drawer
import nwdiag.parser, nwdiag.builder, nwdiag.drawer
import packetdiag.parser, packetdiag.builder, packetdiag.drawer
import rackdiag.parser, rackdiag.builder, rackdiag.drawer
import seqdiag.parser, seqdiag.builder, seqdiag.drawer

def processBookItem(src_path, item):
    if 'Chapter' in item:
        processChapter(src_path, item['Chapter'])

def processChapter(src_path, ch):
    file_path = src_path + "/" + ch['path']
    
    # parse content
    while True:
        group = re.search(r'^\s*```\s*(actdiag|blockdiag|nwdiag|packetdiag|rackdiag|seqdiag)\s*(\{.*?\})\s*```\s*$', ch['content'], re.DOTALL|re.MULTILINE)
        if group:
            try:
                # Get svg
                diagModule = sys.modules[group.group(1)]
                tree = diagModule.parser.parse_string(group.group(2))
                diagram = diagModule.builder.ScreenNodeBuilder.build(tree)
                draw = diagModule.drawer.DiagramDraw('SVG', diagram)
                draw.draw()
                svg = draw.save()

                # Remove svg header
                svg = re.search('<svg .*</svg>', draw.save(), re.DOTALL).group(0)

                # Handle `// max_img_width = xxxx;`
                # User can use this way to set the max width of svg.
                maxWidth = re.search(r'//\s*max_img_width\s*=\s*(\d+)\s*;', group.group(2))
                if maxWidth:
                    svg = svg.replace('<svg ', '<svg style="max-width: {}px;" '.format(maxWidth.group(1)), 1)
                
                # Insert svg into content
                ch['content'] = ch['content'].replace(group.group(0), '\n' + svg + '\n', 1)
            except:
                print >> sys.stderr, "{} [WARN] Parse {} in {} failed, ignore it.".format(datetime.datetime.now().strftime("%Y-%m-%d %H:%M:%S"), group.group(1), file_path)
                break
        else:
            break
    
    # process sub items
    for item in ch['sub_items']:
        processBookItem(src_path, item)

def main():
    if 'supports' in sys.argv:
        sys.exit(0)

    (config, book) = json.loads(sys.stdin.readlines()[0])
    src_path = config['config']['book']['src']
    sections = book['sections']
    for item in sections:
        processBookItem(src_path, item)
    print json.dumps(book)

if __name__ == '__main__':
    main()