The Arcology Site Engine

Arcology Routing Logic


This is a way to abstract URL logic between the development domain and the production domain without so much fuss. It's a pair of modules that have an identical export. Each one has:

I've considered putting URL generation in these and may yet do so but that is in the arcology.key.ArcologyKey. Probably a mistake.

Shared Functions

Load up the template and the imports that render_page_from_key uses…

from fastapi import Request
from sqlmodel import Session
from fastapi.templating import Jinja2Templates
from typing import Optional

from arcology.arroyo import Page, engine
import arcology.html as html

from arcology.config import get_settings, Environment

templ_dir = "arcology/templates"
templates = Jinja2Templates(directory=templ_dir)

This thing is responsible for loading the Arcology Page, and generating an HTML response and packaging it in to a FastAPI response format. It does a lot and the fact that it's pulling modules from all over the code base gives me great anxiety! this is probably something to really consider refactoring or putting better abstractions in to the Page module… or maybe not.

import asyncio

from fastapi import HTTPException

from arcology.feeds import make_feed_entries

async def render_page_from_key(request: Request, key: str, engine, site) -> Optional[templates.TemplateResponse]:
  with Session(engine) as session:
    p = Page.from_key(key, session)
    if p is None:
      raise HTTPException(status_code=404, detail="Page not found.")
    dhtml = await asyncio.create_task(p.document_html())
    bhtml = await asyncio.create_task(p.backlink_html())
    document = html.rewrite_html(dhtml, session)
    backlink = html.rewrite_html(bhtml, session)
    feeds = make_feed_entries(p.get_site().key, session)

    return templates.TemplateResponse("page.html.j2", dict(

NEXT This routing split between local and prod doesn't work because the routes aren't domain aware. and very greedy.

[#A] Arcology Domain-Aware Routing

There are only a handful of routes here, and they're, frankly, janky. A handful of static routes feed functionality in other parts of the site, but most of the heavy-lifting is done below in the public_router function…

from fastapi import FastAPI, Request
from sqlmodel import Session
from fastapi.responses import HTMLResponse, FileResponse, Response

from arcology.routing.util import render_page_from_key, templates, crawlable_pages_for_site
from arcology.feeds import render_feed_from_file
from arcology.arroyo import engine
from arcology.key import ArcologyKey
from arcology.arroyo import Keyword
from arcology.sigma import sigma

def decorate_app(app: FastAPI) -> FastAPI:




  return app

GET /robots.txt

Inside of the cache whether a Page contains an #+ARCOLOGY_ALLOW_CRAWL file property which is not set to nil. Based on this, it's possible to create an robots.txt entry which only exposes pages I explicitly want crawled.

import logging
@app.get("/robots.txt", response_class=FileResponse, name="robots-txt")
async def robots_txt(request: Request):
  with Session(engine) as session:
    key = ArcologyKey.from_request(request).site_key
    crawlable_pages = crawlable_pages_for_site(key, session)
    return templates.TemplateResponse("robots.txt.j2", dict(
User-Agent: *
Disallow: / 
Allow: /static/css
{%- for page in pages %}
{%- set key = page.get_arcology_key() %}
{%- if == "index" %}
Allow: /$
{%- else %}
Allow: /{{}}$
{%- endif %}
{%- endfor %}

this goes in the Shared Functions module because I'm bad at information architecture.

from sqlmodel import select, SQLModel, Session

import arcology.arroyo as arroyo
from arcology.parse import *

def crawlable_pages_for_site(site_key: str, session: Session):
  q = select(arroyo.Page) \
    .where( \
  return session.exec(q).all()

GET /sitemap and /sitemap/json

Use SigmaJS to generate the Arcology Sitemap.

@app.get("/sitemap/", response_class=HTMLResponse, name="sitemap_page")
async def sitemap(request: Request):
  site = ArcologyKey.from_request(request).site
  return templates.TemplateResponse("sitemap.html.j2", dict(

@app.get("/sitemap/json", name="sitemap_json")
async def sitemap(request: Request):
  return sigma(engine)

GET /{key}.xml

This is a shortcut in to the public router below for Arcology Feed Generator files

@app.get("/{sub_key:path}.xml", response_class=Response, name="feed-route")
async def feed_route(request: Request, sub_key: str):
  sub_key += ".xml" # dark laughter
  return Response(content=(await public_router(request, sub_key)), media_type="application/atom+xml")

GET /{key}/?

This does all the heavy lifting:

@app.get("/{sub_key:path}", response_class=HTMLResponse, name="base-route")
@app.get("/{sub_key:path}/", response_class=HTMLResponse, name="base-route")
async def public_router(request: Request, sub_key: str):
  key = None

  if request.headers.get('host',"").startswith('localhost'):
    key = ArcologyKey(key=sub_key)
    key = ArcologyKey.from_request(request)

  with Session(engine) as session:
    kw = Keyword.get("ARCOLOGY_FEED", key.key, session)
    if kw is not None:
      return await render_feed_from_file(request, kw.filename(), engine,

  return await render_page_from_key(request, key.key, engine,