164796899-feature: pagination support for articles

- modify getAllArticles controller
- write integration tests
- add middlewares

[Delivers #164796899]

src/controllers/article.js

@@ -1,6 +1,7 @@
 import sequelize from 'sequelize';
 import { slug } from '../utils/article';
 import { responseHandler, responseFormat, errorResponseFormat } from '../utils';
+import { findAndCount } from '../utils/query';
 import { Article, Comment, Bookmark, Report, Sequelize } from '../models';
 
 /**
@@ -209,21 +210,31 @@ export const reportArticle = async (req, res) => {
  */
 export const getAllArticles = async (req, res) => {
   try {
+    let { query: { page, limit } } = req;
+    const regex = new RegExp('^\\d+$');
+    page = regex.test(page) ? parseInt(page, 10) : 1;
+    limit = regex.test(limit) ? parseInt(limit, 10) : 10;
+    const { count } = await findAndCount(Article, { where: {} });
+    const pages = Math.ceil(count / limit);
+    const offset = limit * (page - 1);
+    const paginate = { limit, offset, subQuery: false };
+
     const articles = await Article.findAll({
       where: { published: true },
       order: [['createdAt', 'ASC']],
       group: ['Article.id', 'comments.id'],
+      ...paginate,
       include: [{
         model: Comment,
         as: 'comments',
         attributes: [
           [sequelize.fn('COUNT', sequelize.col('comments.id')), 'all'],
         ],
-        group: 'comments.id',
-      }]
+      }],
     });
-    return responseHandler(res, 200, { status: 'success', data: articles });
+    return responseHandler(res, 200, { status: 'success', data: articles, pages, });
   } catch (error) {
+    console.log(error);
     return responseHandler(res, 500, { status: 'error', message: 'An internal server error occured!' });
   }
 };

src/middlewares/articles.js

@@ -21,7 +21,6 @@ export const articleValidation = async (req, res, next) => {
   next();
 };
 
-
 /**
  *@name verifyArticle
  *@description Middleware for verifying that article exists
@@ -40,7 +39,6 @@ export const verifyArticle = async (req, res, next) => {
   next();
 };
 
-
 /**
  *@name isAuthor
  *@description Middleware for checking if an author has the privilege to edit an article
@@ -56,6 +54,7 @@ export const isAuthor = async (req, res, next) => {
   if (authorId !== userId && role !== 'admin') { return responseHandler(res, 403, { status: 'error', message: 'You don\'t have access to manage this article!', }); }
   next();
 };
+
 /**
  * @function articleReportValidation
  * @param {Request} req
@@ -107,3 +106,33 @@ export const getArticleHandler = async (req, res, next) => {
     default: return getAllArticles(req, res, next);
   }
 };
+
+/**
+ *@name getArticleHandler
+ *@description Middleware for handling requests for an article
+ * @param {object} req Request object
+ * @param {object} res Response object
+ * @param {function} next Calls the necxt function/action
+ * @returns {function} Calls next function/action
+ */
+export const checkQueryParams = async (req, res, next) => {
+  const queryParams = req.query;
+  const allowedQueryFields = ['page', 'limit'];
+  if (typeof queryParams !== 'object') { return next(); }
+  // eslint-disable-next-line no-restricted-syntax
+  for (const query in queryParams) {
+    // eslint-disable-next-line no-prototype-builtins
+    if (queryParams.hasOwnProperty(query)) {
+      if (!allowedQueryFields.includes(query)) {
+        return responseHandler(res, 400, { status: 'fail', message: 'Invalid request parameter supplied!' });
+      }
+      if (query === 'page' || query === 'limit') {
+        const param = parseInt(queryParams[query], 10);
+        if (param < 1) {
+          return responseHandler(res, 400, { status: 'fail', message: `${query.toUpperCase()} should not be less than 1!` });
+        }
+      }
+    }
+  }
+  return next();
+};

src/routers/index.js

@@ -29,7 +29,8 @@ import {
   isAuthor,
   getArticleHandler,
   articleReportValidation,
-  articleTagValidation
+  articleTagValidation,
+  checkQueryParams,
 } from '../middlewares/articles';
 import { checkParam } from '../middlewares/checkParam';
 import checkEditBody from '../middlewares/editProfileValidator';
@@ -61,7 +62,7 @@ router
  */
 router
   .route('/articles/:id?')
-  .get(getArticleHandler)
+  .get(checkQueryParams, getArticleHandler)
   .post(Auth.authenticateUser, articleValidation, addArticle)
   .delete(checkParam, Auth.authenticateUser, verifyArticle, isAuthor, deleteArticle)
   .put(checkParam, Auth.authenticateUser, articleValidation, verifyArticle, isAuthor, editArticle);

src/utils/index.js

@@ -40,14 +40,9 @@ export const validateParameters = async (body) => {
  * @param {object} payload The response data to the user
  * @returns {object} Returns the response object
  */
-export const responseHandler = (res, code, payload) => {
-  const { data, status, message } = payload;
-  return res.status(code).json({
-    status,
-    message,
-    data,
-  });
-};
+export const responseHandler = (res, code, payload) => res.status(code).json({
+  ...payload,
+});
 
 /**
  * @function errorResponseFormat

src/utils/query.js

@@ -1,6 +1,25 @@
+/**
+ * @name findById
+ * @description This is function for getting records by primary key
+ * @param {object} Model The object model
+ * @param {string} id The primary key
+ * @returns {object} Returns record query
+ */
 export const findById = async (Model, id) => {
   const record = await Model.findByPk(id);
   return record;
 };
 
+/**
+ * @name findAndCount
+ * @description This is function for counting records via query
+ * @param {object} Model The object model
+ * @param {object|null|void} param The certain conditionals for the query to run
+ * @returns {object} Returns record query
+ */
+export const findAndCount = async (Model, param = null) => {
+  const record = await Model.findAndCountAll(param);
+  return record;
+};
+
 export default findById;

tests/integration/article.test.js

@@ -21,7 +21,6 @@ describe('GET /api/v1/articles/:id?', () => {
   it('Should return status: 200 for getting all articles', (done) => {
     agent.get('/api/v1/articles')
       .set('Authorization', JWT_TOKEN)
-      .send(ARTICLE)
       .end((_err, res) => {
         expect(res).to.have.status(200);
         done();
@@ -31,13 +30,53 @@ describe('GET /api/v1/articles/:id?', () => {
   it('Should return status: 200 for getting a single article', (done) => {
     agent.get('/api/v1/articles/979eaa2e-5b8f-4103-8192-4639afae2ba7')
       .set('Authorization', JWT_TOKEN)
-      .send(ARTICLE)
       .end((_err, res) => {
         expect(res).to.have.status(200);
         done();
       });
   });
 
+  it('Should return status: 200 for getting all articles in paginated format when valid query parameters are supplied', (done) => {
+    agent.get('/api/v1/articles?page=1&limit=5')
+      .set('Authorization', JWT_TOKEN)
+      .end((_err, res) => {
+        expect(res).to.have.status(200);
+        expect(res.body.status).to.equal('success');
+        done();
+      });
+  });
+
+  it('Should return status: 400 for getting all articles in paginated format when invalid query parameters value are supplied', (done) => {
+    agent.get('/api/v1/articles?page=1&limit=0')
+      .set('Authorization', JWT_TOKEN)
+      .end((_err, res) => {
+        expect(res).to.have.status(400);
+        expect(res.body.status).to.equal('fail');
+        done();
+      });
+  });
+
+  it('Should return status: 400 for getting all articles in paginated format when invalid query parameters are supplied', (done) => {
+    agent.get('/api/v1/articles?page=1&limit=0&atabolebo=1000000')
+      .set('Authorization', JWT_TOKEN)
+      .end((_err, res) => {
+        expect(res).to.have.status(400);
+        expect(res.body.status).to.equal('fail');
+        done();
+      });
+  });
+
+  it('Should return status: 200 with an empty array when page parameter exceeds available records number', (done) => {
+    agent.get('/api/v1/articles?page=200&limit=5')
+      .set('Authorization', JWT_TOKEN)
+      .end((_err, res) => {
+        expect(res).to.have.status(200);
+        expect(res.body.data.length).to.equal(0);
+        done();
+      });
+  });
+
+
   after(async (done) => {
     app.close();
     app = null;
@@ -73,6 +112,15 @@ describe('POST /api/v1/articles', () => {
       });
   });
 
+  it('Should return status: 400 when authorization token is invalid', (done) => {
+    agent.post('/api/v1/articles')
+      .send(ARTICLE)
+      .end((_err, res) => {
+        expect(res).to.have.status(400);
+        done();
+      });
+  });
+
   after(async (done) => {
     app.close();
     app = null;

tests/mock/user.js

@@ -62,3 +62,5 @@ export const editPayload = {
   bio: 'I Love Javascript',
   imageUrl: 'http://waterease.herokuapp.com/images/board/comfort.com'
 };
+
+export const FAKE_USER = 'eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9.eyJpZCI6Ijg4ZDkwOGQwLTdmYWYtNDZiNC1hZTQ2LWNhZWE0MzVlY2I4MiIsImZ1bGxOYW1lIjoiY2hpa2UgYXJ0aHVyIiwiYmlvIjpudWxsLCJlbWFpbCI6ImFuZGVsYVV0b2JpbGlibGl5YUBnbWFpbC5jb20iLCJ1c2VybmFtZSI6ImFydGh1cnRvIiwicm9sZSI6ImF1dGhvciIsImlhdCI6MTU1NTYwMDg3MywiZXhwIjoxNTU1Njg3MjczfQ.YrQFpEPJP4fqLSALXwdwQZtDAogruEdH9EtoLz1qZPA';