implemented query filtering for pilots

Dockerfile

@@ -17,6 +17,7 @@ RUN apk update && \
     # apk add --no-cache git && \
 
 COPY --chown=node:node package*.json ./
+COPY --chown=node:node assets ./assets
 
 USER node
 

assets/filter.peggy

@@ -0,0 +1,38 @@
+Filter
+	= ComparingFilter / CombiningFilter
+
+Filters
+	= f:Filter _ fs:Filters {return [f, ...fs]}
+  / f:Filter {return [f]}
+
+
+CombiningFilter
+  = "(" comb:Combinator _ filters:Filters ")" {return {[comb]: filters}}
+
+ComparingFilter
+  = "(" _ field:Field _ comp:Comparator _ value:String _ ")" {return {[field]: {[comp]: value}}}
+
+Field =
+  s:String {
+    switch(s) {
+      default: return s; // PLACEHOLDER_REPLACE_THIS_LINE
+    }
+  }
+
+String "string"
+  = s:[a-zA-Z0-9]+ {return s.join('')}
+
+Comparator "comparator"
+  = "<=" {return "$lte"}
+  / ">=" {return "$gte"}
+  / "!=" {return "$neq"}
+  / "=" {return "$eq"}
+  / ">" {return "$gt"}
+  / "<" {return "$lt"}
+
+Combinator "combinator"
+	= "|" {return "$or"}
+  / "&" {return "$and"}
+
+_ "whitespace"
+	= [ \t\n\r]*

package.json

@@ -41,6 +41,7 @@
     "ms": "2.1.3",
     "nest-winston": "1.9.4",
     "nestjs-joi": "1.10.0",
+    "peggy": "4.0.2",
     "point-in-polygon": "^1.1.0",
     "winston": "3.11.0"
   },

src/backend/pilot/pilot.controller.ts

@@ -1,7 +1,9 @@
-import { Body, Controller, Delete, Get, Param, Patch, Post } from '@nestjs/common';
+import { BadRequestException, Body, Controller, Delete, Get, Param, Patch, Post, Query } from '@nestjs/common';
 import { ApiTags } from '@nestjs/swagger';
 import { JoiPipe } from 'nestjs-joi';
 
+import logger from '../logger';
+
 import { PilotDto, PilotCallsignValidator } from './pilot.dto';
 import { PilotService } from './pilot.service';
 
@@ -15,8 +17,19 @@ export class PilotController {
   ) {}
 
   @Get('/')
-  async getAllPilots() {
-    const pilots = await this.pilotService.getAllPilots();
+  async getAllPilots(@Query('filter') filter = '') {
+    let parsedFilter = {};
+
+    if (filter) {
+      try {
+        parsedFilter = this.pilotService.processFilter(filter);
+      } catch (error) {
+        throw new BadRequestException(error.message);
+      }
+      logger.debug('filter: %s - parsedFilter: %o', filter, parsedFilter);
+    }
+
+    const pilots = await this.pilotService.getPilots(parsedFilter);
 
     return {
       count: pilots.length,

src/backend/pilot/pilot.service.ts

@@ -1,6 +1,7 @@
 import { ConflictException, Inject, Injectable, NotFoundException, forwardRef } from '@nestjs/common';
 import Agenda from 'agenda';
 import { FilterQuery } from 'mongoose';
+import { Parser } from 'peggy';
 
 import { AirportService } from '../airport/airport.service';
 import { CdmService } from '../cdm/cdm.service';
@@ -25,6 +26,17 @@ export class PilotService {
   ) {
     this.agenda.define('PILOT_cleanupPilots', this.cleanupPilots.bind(this));
     this.agenda.every('10 minutes', 'PILOT_cleanupPilots');
+
+    this.parser = this.utilsService.generateFilter({
+      adep: 'flightplan.adep',
+      ades: 'flightplan.ades',
+    }, true);
+  }
+
+  private parser: Parser;
+
+  processFilter(filter: string): FilterQuery<Pilot> {
+    return this.parser.parse(filter);
   }
 
   getPilots(filter: FilterQuery<Pilot>): Promise<PilotDocument[]> {

src/backend/utils/utils.service.ts

@@ -1,6 +1,8 @@
 import crypto from 'node:crypto';
+import fs from 'node:fs';
 
 import { Injectable } from '@nestjs/common';
+import peggy, { Parser } from 'peggy';
 
 import logger from '../logger';
 
@@ -113,4 +115,50 @@ export class UtilsService {
   generateRandomBytes(length = 32, encoding: BufferEncoding = 'base64') {
     return crypto.randomBytes(length).toString(encoding);
   }
+
+  generateFilter(fieldMapping = {}, disallowUndefinedFieldNames = false): Parser {
+    const baseFilter = fs.readFileSync('assets/filter.peggy', { encoding: 'utf8' });
+
+    if (Object.values(fieldMapping).length == 0 && disallowUndefinedFieldNames) {
+      return peggy.generate(baseFilter);
+    }
+
+    const lines = baseFilter.replace(/\r\n/gm, '\n').split('\n');
+    let line = -1;
+    let prefix = '';
+
+    // find line to replace
+    for (let i = 0; i < lines.length; i++) {
+      const lstring = lines[i];
+      if (lstring.includes('PLACEHOLDER_REPLACE_THIS_LINE')) {
+        line = i;
+        const match = lstring.match(/([ \t]+)[\w\W\d ]*/i);
+
+        if (match) {
+          prefix = match[1];
+        }
+
+        break;
+      }
+    }
+
+    if (line == -1) {
+      return peggy.generate(baseFilter);
+    }
+
+    const fieldsLines = Object.entries(fieldMapping)
+      .map(([k, v]) => `${prefix}case '${k}': return '${v}'`);
+
+    if (disallowUndefinedFieldNames) {
+      fieldsLines.push(`${prefix}default: throw new Error('"' + s + '" is not an accepted field name');`);
+    } else {
+      fieldsLines.push(`${prefix}default: return s;`);
+    }
+
+    lines.splice(line, 1, ...fieldsLines);
+
+    const newFilter = lines.join('\n');
+
+    return peggy.generate(newFilter);
+  }
 }