@trailstash/ultra/lib/queryProviders/postpass.js

A web based tool for making MapLibre GL maps with data from sources such as Overpass, GeoJSON, GPX, KML, TCX, etc

import { setQueryBounds } from "../bounds.js";

import { layers, popupTemplate, popupContextBuilder } from "./osm.js";

const flattenPropertiesAndInferIdAndType = (geoJSON) => {
  // prety major assumption basked into this as Postpass executes arbitrary SQL so the returned
  // data could be anything. This assumes that the query returns un-renamed columns.
  geoJSON.features = geoJSON.features.map((f) => {
    const properties = {};
    if (f.properties.osm_id) {
      properties["@id"] = f.properties.osm_id;
      properties["@type"] = f.properties.osm_type;
    }
    if (f.properties.tags) {
      for (const [k, v] of Object.entries(f.properties.tags)) {
        properties[k] = v;
      }
    }
    for (const [k, v] of Object.entries(f.properties)) {
      properties[k] = v;
    }
    return {
      ...f,
      properties,
    };
  });
  return geoJSON;
};

const postpass = {
  source: async function (query, controller, { server, bounds }) {
    if (!server) {
      server = "https://postpass.geofabrik.de/api/0.2/interpreter";
    }
    const resp = await fetch(server, {
      method: "POST",
      body: new URLSearchParams([["data", query]]),
      signal: controller.signal,
      headers: {
        "Content-Type": "application/x-www-form-urlencoded",
        Accept: "application/json",
      },
    });
    if (!resp.ok) {
      throw new Error(
        `Postpass API returned ${resp.status}:\n${await resp.text()}`,
      );
    }
    const data = await resp.json();
    return {
      type: "geojson",
      data: flattenPropertiesAndInferIdAndType(data),
      attribution:
        '\u003Ca href="https://www.openstreetmap.org/copyright" target="_blank"\u003E© OpenStreetMap contributors\u003C/a\u003E',
      generateId: true,
    };
  },
  layers,
  popupTemplate,
  popupContextBuilder,
};
export default postpass;