Used async/await handler; Always assign new knex connection to preven…

…t left open connections; Refactored response-mapping-templates

handler.js

@@ -2,135 +2,79 @@ import { getAuthor, getAuthors } from './resolvers/author-resolver';
 import { getPost, getPosts, addPost, updatePost, deletePost } from './resolvers/post-resolver';
 import { getComment, getComments, addComment, updateComment, deleteComment } from './resolvers/comment-resolver';
 
+const connection = require('./knexfile');
+const knexLib = require('knex');
 
-exports.graphqlHandler = (event, context, callback) => {
+exports.graphqlHandler = async (event, context) => {
   context.callbackWaitsForEmptyEventLoop = false;
   console.log('Received event {}', JSON.stringify(event, 3));
 
-  switch (event.field) {
-    case 'getAuthor': {
-      getAuthor(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'getAuthors': {
-      getAuthors(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'getPost': {
-      getPost(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'getPosts': {
-      getPosts(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'getComment': {
-      getComment(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'getComments': {
-      getComments(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'addPost': {
-      addPost(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'updatePost': {
-      updatePost(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'deletePost': {
-      deletePost(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'addComment': {
-      addComment(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'updateComment': {
-      updateComment(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'deleteComment': {
-      deleteComment(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'comments': {
-      getComments(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'author': {
-      getAuthor(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    case 'posts': {
-      getPosts(event.arguments).then(result => {
-        callback(null, result);
-      }).catch(error => {
-        callback(error, null);
-      });
-      break;
-    }
-    default: {
-      callback(`Unknown field, unable to resolve ${event.field}`, null);
-      break;
-    }
+  const knex = knexLib(process.env.NODE_ENV === 'production' ? connection.production : connection.dev);
+
+  try {
+    let result;
+
+    switch (event.field) {
+      case 'author':
+      case 'getAuthor': {
+        result = await getAuthor(knex, event.arguments);
+        break;
+      }
+      case 'getAuthors': {
+        result = await getAuthors(knex, event.arguments);
+        break;
+      }
+      case 'getPost': {
+        result = await getPost(knex, event.arguments);
+        break;
+      }
+      case 'posts':
+      case 'getPosts': {
+        result = await getPosts(knex, event.arguments);
+        break;
+      }
+      case 'getComment': {
+        result = await getComment(knex, event.arguments);
+        break;
+      }
+      case 'comments':
+      case 'getComments': {
+        result = await getComments(knex, event.arguments);
+        break;
+      }
+      case 'addPost': {
+        result = await addPost(knex, event.arguments);
+        break;
+      }
+      case 'updatePost': {
+        result = await updatePost(knex, event.arguments);
+        break;
+      }
+      case 'deletePost': {
+        result = await deletePost(knex, event.arguments);
+        break;
+      }
+      case 'addComment': {
+        result = await addComment(knex, event.arguments);
+        break;
+      }
+      case 'updateComment': {
+        result = await updateComment(knex, event.arguments);
+        break;
+      }
+      case 'deleteComment': {
+        result = await deleteComment(knex, event.arguments);
+        break;
+      }
+      default: {
+        throw `Unknown field, unable to resolve ${event.field}`;
+      }
+    }
+    return result;
+  } catch (error) {
+    console.log('Lambda error:', error);
+    return Promise.reject(error);
+  } finally {
+    knex.destroy();
   }
 };

knexfile.js

@@ -1,4 +1,3 @@
-// eslint-disable-next-line
 const mysql = require('mysql');
 
 module.exports = {

resolvers/author-resolver.js

@@ -1,31 +1,12 @@
-const connection = require('./../knexfile');
-const knex = require('knex')(process.env.NODE_ENV === 'production' ? connection.production : connection.dev);
-
-async function getAuthor(args) {
-  try {
-    const getAuthorQuery = knex('author')
-      .where('id', args.id)
-      .first();
-
-    const result = await getAuthorQuery;
-
-    return result
-  } catch (err) {
-    console.log(err);
-  }
+async function getAuthor(knex, args) {
+  return await knex('author')
+    .where('id', args.id)
+    .first();
 }
 
-async function getAuthors(args) {
-  try {
-    const getAuthorsQuery = knex('author')
-      .orderBy('lastname', 'asc');
-
-    const result = await getAuthorsQuery;
-
-    return result
-  } catch (err) {
-    console.log(err);
-  }
+async function getAuthors(knex, args) {
+  return await knex('author')
+    .orderBy('lastname', 'asc');
 }
 
 export { getAuthor, getAuthors };