todo,todo-backend: add support for filtering

Signed-off-by: Patrik Oldsberg <poldsberg@gmail.com>

plugins/todo-backend/src/service/TodoReaderService.ts

@@ -36,6 +36,13 @@ type Options = {
   defaultPageSize?: number;
 };
 
+function wildcardRegex(str: string): RegExp {
+  const pattern = str
+    .replace(/[.+?^${}()|[\]\\]/g, '\\$&')
+    .replace(/\*/g, '.*');
+  return new RegExp(`^${pattern}$`, 'i');
+}
+
 export class TodoReaderService implements TodoService {
   private readonly todoReader: TodoReader;
   private readonly catalogClient: CatalogClient;
@@ -62,7 +69,6 @@ export class TodoReaderService implements TodoService {
 
     const url = this.getEntitySourceUrl(entity);
     const todos = await this.todoReader.readTodos({ url });
-    const totalCount = todos.items.length;
 
     let limit = req.limit ?? this.defaultPageSize;
     if (limit < 0) {
@@ -77,7 +83,15 @@ export class TodoReaderService implements TodoService {
     }
 
     let items = todos.items;
-    const { orderBy } = req;
+    const { orderBy, filters } = req;
+
+    if (filters) {
+      for (const { field, value } of filters) {
+        const pattern = wildcardRegex(value);
+        items = items.filter(item => item[field]?.match(pattern));
+      }
+    }
+
     if (orderBy) {
       const dir = orderBy.direction === 'asc' ? 1 : -1;
       const field = orderBy.field;
@@ -98,7 +112,7 @@ export class TodoReaderService implements TodoService {
 
     return {
       items: items.slice(offset, offset + limit),
-      totalCount,
+      totalCount: items.length,
       offset,
       limit,
     };

plugins/todo-backend/src/service/router.ts

@@ -20,7 +20,7 @@ import express from 'express';
 import Router from 'express-promise-router';
 import { TodoService } from './types';
 
-const ALLOWED_ORDER_BY_FIELDS = [
+const TODO_FIELDS = [
   'text',
   'tag',
   'author',
@@ -43,11 +43,8 @@ export async function createRouter(
   router.get('/v1/todos', async (req, res) => {
     const offset = parseIntegerParam(req.query.offset, 'offset query');
     const limit = parseIntegerParam(req.query.limit, 'limit query');
-    const orderBy = parseOrderByParam(
-      req.query.orderBy,
-      'orderBy query',
-      ALLOWED_ORDER_BY_FIELDS,
-    );
+    const orderBy = parseOrderByParam(req.query.orderBy, TODO_FIELDS);
+    const filters = parseFilterParam(req.query.filter, TODO_FIELDS);
 
     const entityRef = req.query.entity;
     if (entityRef && typeof entityRef !== 'string') {
@@ -67,6 +64,7 @@ export async function createRouter(
       offset,
       limit,
       orderBy,
+      filters,
     });
     res.json(todos);
   });
@@ -90,22 +88,21 @@ function parseIntegerParam(str: unknown, ctx: string): number | undefined {
 
 function parseOrderByParam<T extends readonly string[]>(
   str: unknown,
-  ctx: string,
   allowedFields: T,
 ): { field: T[number]; direction: 'asc' | 'desc' } | undefined {
   if (str === undefined) {
     return undefined;
   }
   if (typeof str !== 'string') {
-    throw new InputError(`invalid ${ctx}, must be a string`);
+    throw new InputError(`invalid orderBy query, must be a string`);
   }
   const [field, direction] = str.split('=');
   if (!field) {
-    throw new InputError(`invalid ${ctx}, field name is empty`);
+    throw new InputError(`invalid orderBy query, field name is empty`);
   }
   if (direction !== 'asc' && direction !== 'desc') {
     throw new InputError(
-      `invalid ${ctx}, order direction must be 'asc' or 'desc'`,
+      `invalid orderBy query, order direction must be 'asc' or 'desc'`,
     );
   }
 
@@ -116,3 +113,44 @@ function parseOrderByParam<T extends readonly string[]>(
   }
   return { field, direction };
 }
+
+function parseFilterParam<T extends readonly string[]>(
+  str: unknown,
+  allowedFields: T,
+): { field: T[number]; value: string }[] | undefined {
+  if (str === undefined) {
+    return undefined;
+  }
+
+  const filters = new Array<{ field: T[number]; value: string }>();
+
+  const strs = [str].flat();
+  for (const filterStr of strs) {
+    if (typeof filterStr !== 'string') {
+      throw new InputError(
+        `invalid filter query, must be a string or list of strings`,
+      );
+    }
+    const splitIndex = filterStr.indexOf('=');
+    if (splitIndex <= 0) {
+      throw new InputError(
+        `invalid filter query, must separate field from value using '='`,
+      );
+    }
+
+    const field = filterStr.slice(0, splitIndex);
+    if (!allowedFields.includes(field)) {
+      throw new InputError(
+        `invalid filter field, must be one of ${allowedFields.join(', ')}`,
+      );
+    }
+
+    const value = filterStr.slice(splitIndex + 1);
+    if (!value) {
+      throw new InputError(`invalid filter query, value may not be empty`);
+    }
+    filters.push({ field, value });
+  }
+
+  return filters;
+}

plugins/todo-backend/src/service/types.ts

@@ -17,14 +17,21 @@
 import { EntityName } from '@backstage/catalog-model';
 import { TodoItem } from '../lib';
 
+type Fields = 'text' | 'tag' | 'author' | 'viewUrl' | 'repoFilePath';
+
 export type ListTodosRequest = {
   entity?: EntityName;
   offset?: number;
   limit?: number;
   orderBy?: {
-    field: 'text' | 'tag' | 'author' | 'viewUrl' | 'repoFilePath';
+    field: Fields;
     direction: 'asc' | 'desc';
   };
+  filters?: {
+    field: Fields;
+    /** Value to filter by, with '*' used as wildcard */
+    value: string;
+  }[];
 };
 
 export type ListTodosResponse = {