app.py

import configparser
import logging
from notion.client import NotionClient
from notion.block import HeaderBlock, SubheaderBlock, SubsubheaderBlock, TextBlock, PageBlock

appname = "Notion Backlinks Creator"
version = "1.0.1"

#Configuration load
config = configparser.ConfigParser()
config.read('config.ini')

#Set logging configuration
# logging.basicConfig(level=config.get('runtime','logging'))
log = logging.getLogger(appname)
log.setLevel(config.get('runtime','logging'))

#Set screen log handler
log.addHandler(logging.StreamHandler())

#Set file log handler
log.addHandler(logging.FileHandler(config.get('runtime','logfile'))) if config.get('runtime','logfile') else None

#Notion configuration read
notion_api_token = config.get('notion', 'api_token')
notion_collection_url = config.get('notion', 'collection_url')

#Notion user preferences read
notion_reflink_section  = config.get('notion', 'reflink_section')
notion_backlink_section = config.get('notion', 'backlink_section')

#Welcome message
print(f"Welcome to {appname} v{version}")

#Connect to Notion api
print(f" connecting to Notion API")
client = NotionClient(token_v2=notion_api_token)

#Open given collection page
page = client.get_block(notion_collection_url)
print(f" loading page {page.title}")

#Verify page type, must be a collection, preferrably without filters
if page.type != 'collection_view_page':
    log.critical('The given page must be a collection (database), not a simple page! Exiting.')
    exit()

#Store all page links within collection (tuples: from.name, from.id, to.name, to.id)
links = []

#LOAD COLLECTION AND GRAB LINKS
cv = client.get_collection_view(notion_collection_url)
print(f" loading collection {cv.parent.title}:{cv.name}")

#Iterate collection elements (rows)
for row in cv.collection.get_rows():
    test_for_link = False
    log.info(f"  row [{row.id}] {row.title}")

    #Iterate element children
    for child in row.children:
        log.debug(f"   child [{child.type}] {getattr(child, 'title', child.type)}")

        #Test if we reached reflink or backlink section which may contains links?
        if hasattr(child, 'title') and (child.title.startswith(notion_reflink_section) or child.title.startswith(notion_backlink_section)):
            test_for_link = True
            continue

        #If there are no more links assume we left the links section
        if test_for_link and child.type != 'page':
            test_for_link = False
            continue

        #If we are in links section test the current element for page link
        if test_for_link and child.type == 'page':
            links.append((row.title, row.id, child.title, child.id))
            log.debug(f"   link found from {links[-1][0]} to {links[-1][2]}")


#Inform what we have found
print(f"  links found: {len(links)}")

#Function for testing link's mutual pair in the links collection
def hasPair(link, links):
    for pair in links:
        if pair[3] == link[1] and pair[1] == link[3]:
            return True
    return False


#Store all mutual page links we have to create (tuples: from.name, from.id, to.name, to.id)
links_to_make = []

#LOOKING FOR LINKS WITHOUT MUTUAL LINKS
for x, link in enumerate(links):
    if not hasPair(link, links):
        links_to_make.append(link)
        log.debug(f"  no mutual link from {link[0]} to {link[2]}")

#Inform if we have no backlink to create at all
if not len(links_to_make):
    print(f"  no backlinks to create")
    print(f"Done.")
    exit()


#Sort backlinks by source page (not really needed yet)
links_to_make.sort(key=lambda item: item[3])

print(f"  creating {len(links_to_make)} backlink(s) - please wait")

#Set style for new backlinks section name
backlink_styles = {"H1": HeaderBlock, "H2": SubheaderBlock, "H3": SubsubheaderBlock, "TEXT": TextBlock}
backlink_style = backlink_styles[config.get('notion', 'backlink_style')]

#Iterating all backlinks to create
for link in links_to_make:
    page = client.get_block(link[3])
    log.info(f"    seeking place to backlink {page.title} to {link[0]}")
    
    backlinks_found = False
    last_backlink = None
    
    #Iterating over all page sections
    for child in page.children:
        log.debug(f"    inside child {getattr(child, 'title', child.type)}")
        
        #Set last known page element
        if last_backlink is None or not backlinks_found:
            last_backlink = child

        #Test if we reached backlink section which may contains links?
        if hasattr(child, 'title') and child.title.startswith(notion_backlink_section):
            backlinks_found = True
            last_backlink = child
            continue

        #Find the last link in backlinks section
        if backlinks_found and child.type == 'page':
            last_backlink = child
            continue

    #There were no backlinks section, adding one            
    if not backlinks_found:
        log.debug(f"     {notion_backlink_section} section not found, adding")
        #We add empty space before backlinks section
        new_space_block = page.children.add_new(TextBlock, title="")
        #Then add the backlinks section with configured style (H1, H2, H3 or TEXT)
        new_backlink_block = page.children.add_new(backlink_style, title=notion_backlink_section)
        new_backlink_block.move_to(new_space_block, "after")
        last_backlink = new_backlink_block

    #Actually creating the backlink
    new_block = page.children.add_alias(client.get_block(link[1]))
    print(f"    created backlink from {link[2]} to {link[0]}")

print(f"Finished.")