add geobuf, add attributions

bbox.js

+// based on https://raw.githubusercontent.com/tobinbradley/dirt-simple-postgis-http-api/master/routes/bbox.js
+
 // route query
 const sql = (params, query) => {
     return `

geobuf.js

+// based on https://github.com/tobinbradley/dirt-simple-postgis-http-api/blob/master/routes/geobuf.js
+
+// route query
+const sql = (params, query) => {
+    let bounds = query.bounds ? query.bounds.split(',').map(Number) : null
+    bounds && bounds.length === 3
+      ? (bounds = merc.bbox(bounds[1], bounds[2], bounds[0]))
+      : null
+  
+    return `
+  
+    SELECT 
+      ST_AsGeobuf(q, 'geom')
+    
+    FROM
+    (
+  
+      SELECT
+        ST_Transform(${query.geom_column}, 4326) as geom
+        ${query.columns ? `, ${query.columns}` : ''}
+  
+      FROM
+        ${params.table}
+        ${
+          bounds
+            ? `, (SELECT ST_SRID(${query.geom_column}) as srid FROM ${
+                params.table
+              } LIMIT 1) sq`
+            : ''
+        }
+  
+      -- Optional Filter
+      ${query.filter || bounds ? 'WHERE' : ''}
+      ${query.filter ? `${query.filter}` : ''}
+      ${query.filter && bounds ? 'AND' : ''}
+      ${
+        bounds
+          ? `      
+            ${query.geom_column} &&
+            ST_Transform(
+              ST_MakeEnvelope(${bounds.join()}, 4326), 
+              srid
+            )      
+          `
+          : ''
+      }
+  
+    ) as q; 
+  
+    `
+  }
+
+  
+  module.exports = function(app, pool) {
+/**
+ * @swagger
+ *
+ * /data/geobuf/{table}:
+ *   get:
+ *     description: return table as geobuf
+ *     tags: ['geodata']
+ *     produces:
+ *       - application/x-protobuf
+ *     parameters:
+ *       - name: table
+ *         description: name of table or view
+ *         in: path
+ *         required: true
+ *         type: string
+ *       - name: geom_column
+ *         description: name of geometry column (default 'geom')
+ *         in: query
+ *         required: false
+ *       - name: columns
+ *         description: optional comma seperated list of attribute columns to be added to the mvt geometries
+ *         in: query
+ *         required: false
+ *         type: string
+ *       - name: filter
+ *         description: 'Optional filter parameters for a SQL WHERE statement.'
+ *         in: query
+ *         type: string
+ *         required: false
+ *       - name: bounds
+ *         description: 'Optionally limit output to features that intersect bounding box. Can be expressed as a bounding box (sw.lng, sw.lat, ne.lng, ne.lat) or a Z/X/Y tile (0,0,0).'
+ *         in: query
+ *         type: string
+ *         pattern: '^-?[0-9]{0,20}.?[0-9]{1,20}?(,-?[0-9]{0,20}.?[0-9]{1,20}?){2,3}$'
+ *     responses:
+ *       200:
+ *         description: geojson
+ *       422:
+ *         description: invalid datasource or columnname
+ */
+  app.get('/data/geobuf/:table', async (req, res)=> {
+    if (!req.query.geom_column) {
+        req.query.geom_column = 'geom';
+      }
+      const sqlString = sql(req.params, req.query);
+      try {
+        const result = await pool.query(sqlString);
+        res.set('Content-Type', 'text/x-protobuf').send(result.rows[0].st_asgeobuf);
+      } catch(err) {
+        console.log(err);
+        switch (err.code) {
+            case '42P01':
+                err.name = `table ${req.params.table} does not exist`;
+                break;
+            case '42703':
+                err.name = `column does not exist`;
+                break;
+        }
+        res.status(422).json({error:err})
+      }
+    })
+  }
\ No newline at end of file

geojson.js

-const sm = require('@mapbox/sphericalmercator')
-const merc = new sm({
-  size: 256
-});
+// based on https://raw.githubusercontent.com/tobinbradley/dirt-simple-postgis-http-api/master/routes/geojson.js
 
 // route query
 const sql = (params, query) => {

list_layers.js

+// based on https://raw.githubusercontent.com/tobinbradley/dirt-simple-postgis-http-api/master/routes/list_layers.js
 
 
 const sql = () => {

mvt.js

+// based on https://raw.githubusercontent.com/tobinbradley/dirt-simple-postgis-http-api/master/routes/mvt.js
+
 const sm = require('@mapbox/sphericalmercator');
 const fs = require('fs');
 const merc = new sm({