- Add subscriptions for real time updates / messages in feed
- Add user profile section
- Add "follower" tab
- Clone the project
git clone - Install dependencies
yarn
# or
npm install- Create new AWS Mobile Project
awsmobile init- Add Authentication service
awsmobile user-signin enable- Push configuration to AWS Mobile Hub
awsmobile push
- Create & configure a new AppSync API
- Visit the AWS AppSync console and create a new API.
- In Settings, set the Auth mode to Amazon Cognito User Pool and choose the user pool created in the initial service creation.
-
In index.js on line 11, change
<YOURAPPSYNCENDPOINT>to the endpoint given to you when you created the AppSync API. -
Attach the following Schema:
input CreateFollowingInput {
id: ID
followerId: ID!
followingId: ID!
}
input CreateMessageInput {
messageId: ID
authorId: ID!
createdAt: String
messageInfo: MessageInfoInput!
author: UserInput
}
input CreateUserInput {
userId: ID!
username: String!
}
input DeleteFollowingInput {
id: ID!
}
input DeleteMessageInput {
authorId: ID!
createdAt: String!
}
input DeleteUserInput {
userId: ID!
}
type Following {
id: ID
followerId: ID!
followingId: ID!
}
type FollowingConnection {
items: [Following]
nextToken: String
}
type ListUserConnection {
items: [User]
nextToken: String
}
type Mutation {
createMessage(input: CreateMessageInput!): Message
updateMessage(input: UpdateMessageInput!): Message
deleteMessage(input: DeleteMessageInput!): Message
createUser(input: CreateUserInput!): User
updateUser(input: UpdateUserInput!): User
deleteUser(input: DeleteUserInput!): User
createFollowing(input: CreateFollowingInput!): Following
updateFollowing(input: UpdateFollowingInput!): Following
deleteFollowing(input: DeleteFollowingInput!): Following
}
type Query {
getMessage(authorId: ID!, createdAt: String!): Message
listMessages(first: Int, after: String): MessageConnection
listFollowing: [Following]
getUser(userId: ID!): User
listUsers(first: Int, after: String): ListUserConnection
queryMessagesByAuthorIdIndex(authorId: ID!, first: Int, after: String): MessageConnection
}
type Subscription {
onCreateMessage(messageId: ID, authorId: ID, createdAt: String): Message
@aws_subscribe(mutations: ["createMessage"])
onUpdateMessage(messageId: ID, authorId: ID, createdAt: String): Message
@aws_subscribe(mutations: ["updateMessage"])
onDeleteMessage(messageId: ID, authorId: ID, createdAt: String): Message
@aws_subscribe(mutations: ["deleteMessage"])
onCreateUser(userId: ID, username: String): User
@aws_subscribe(mutations: ["createUser"])
onUpdateUser(userId: ID, username: String): User
@aws_subscribe(mutations: ["updateUser"])
onDeleteUser(userId: ID, username: String): User
@aws_subscribe(mutations: ["deleteUser"])
onCreateFollowing(id: ID, followerId: ID, followingId: ID): Following
@aws_subscribe(mutations: ["createFollowing"])
onUpdateFollowing(id: ID, followerId: ID, followingId: ID): Following
@aws_subscribe(mutations: ["updateFollowing"])
onDeleteFollowing(id: ID, followerId: ID, followingId: ID): Following
@aws_subscribe(mutations: ["deleteFollowing"])
}
type Message {
messageId: ID!
authorId: ID!
messageInfo: MessageInfo!
author: User
createdAt: String
}
type MessageConnection {
items: [Message]
nextToken: String
}
type MessageInfo {
text: String!
}
input MessageInfoInput {
text: String!
}
input UpdateFollowingInput {
id: ID!
followerId: ID
followingId: ID
}
input UpdateMessageInput {
messageId: ID
authorId: ID!
createdAt: String!
}
input UpdateUserInput {
userId: ID!
username: String
}
type User {
userId: ID!
username: String
messages(limit: Int, nextToken: String): MessageConnection
following(limit: Int, nextToken: String): UserFollowingConnection
followers(limit: Int, nextToken: String): UserFollowersConnection
}
type UserConnection {
items: [User]
nextToken: String
}
type UserFollowersConnection {
items: [User]
nextToken: String
}
type UserFollowingConnection {
items: [User]
nextToken: String
}
input UserInput {
userId: ID!
username: String!
}- Create the following DynamoDB Tables
- HeardMessageTable
- HeardFollowingTable
- HeardUserTable
- Add the following indexes:
- In HeardMessageTable, create an
authorId-indexwith theauthorIdas the primary / partition key. - In HeardFollowingTable, create a
followingId-indexwith thefollowingIdas the primary / partition key. - In HeardFollowingTable, create a
followerId-indexwith thefollowerIdas the primary / partition key.
To create an index, click on the table you would like to create an index on, click on the indexes tab, then click Create Index .
- Create the following resolvers:
// request mapping template
{
"version": "2017-02-28",
"operation": "GetItem",
"key": {
"userId": $util.dynamodb.toDynamoDBJson($ctx.source.authorId),
}
}
// response mapping template
$util.toJson($ctx.result)// request mapping template
{
"version" : "2017-02-28",
"operation" : "Scan",
}
// response mapping template
$util.toJson($ctx.result.items)// request mapping template
{
"version": "2017-02-28",
"operation": "GetItem",
"key": {
"userId": $util.dynamodb.toDynamoDBJson($ctx.args.userId),
},
}
// response mapping template
$util.toJson($context.result)// request mapping template
{
"version" : "2017-02-28",
"operation" : "Scan",
"limit": $util.defaultIfNull(${ctx.args.limit}, 20),
"nextToken": $util.toJson($util.defaultIfNullOrBlank($ctx.args.nextToken, null))
}
// response mapping template
$util.toJson($ctx.result.items)// request mapping template
{
"version" : "2017-02-28",
"operation" : "Query",
"index" : "followerId-index",
"query" : {
"expression": "followerId = :id",
"expressionValues" : {
":id" : {
"S" : "${ctx.identity.sub}"
}
}
}
}
// response mapping template
$util.toJson($ctx.result.items)// request mapping template
{
"version": "2017-02-28",
"operation": "Query",
"query": {
"expression": "#authorId = :authorId",
"expressionNames": {
"#authorId": "authorId",
},
"expressionValues": {
":authorId": $util.dynamodb.toDynamoDBJson($ctx.args.authorId),
},
},
"index": "authorId-index",
"limit": $util.defaultIfNull($ctx.args.first, 20),
"nextToken": $util.toJson($util.defaultIfNullOrEmpty($ctx.args.after, null)),
"scanIndexForward": true,
"select": "ALL_ATTRIBUTES",
}
// response mapping template
$util.toJson($context.result)// request mapping template
{
"version": "2017-02-28",
"operation": "PutItem",
"key": {
## If object "id" should come from GraphQL arguments, change to $util.dynamodb.toDynamoDBJson($ctx.args.id)
"id": $util.dynamodb.toDynamoDBJson($util.autoId()),
},
"attributeValues": $util.dynamodb.toMapValuesJson($ctx.args.input),
"condition": {
"expression": "attribute_not_exists(#id)",
"expressionNames": {
"#id": "id",
},
},
}
// response mapping template
$util.toJson($context.result)// request mapping template
{
"version": "2017-02-28",
"operation": "DeleteItem",
"key": {
"id": $util.dynamodb.toDynamoDBJson($ctx.args.input.id),
},
}
// response mapping template
$util.toJson($context.result)// request mapping template
{
"version": "2017-02-28",
"operation": "PutItem",
"key": {
"userId": $util.dynamodb.toDynamoDBJson($ctx.args.input.userId),
},
"attributeValues": $util.dynamodb.toMapValuesJson($ctx.args.input),
"condition": {
"expression": "attribute_not_exists(#userId)",
"expressionNames": {
"#userId": "userId",
},
},
}
// response mapping template
$util.toJson($context.result)// request mapping template
#set($time = $util.time.nowISO8601())
#set($attribs = $util.dynamodb.toMapValues($ctx.args.input))
#set($attribs.createdAt = $util.dynamodb.toDynamoDB($time))
#set($attribs.messageId = $util.dynamodb.toDynamoDB($util.autoId()))
{
"version": "2017-02-28",
"operation": "PutItem",
"key": {
"authorId": $util.dynamodb.toDynamoDBJson($ctx.args.input.authorId),
"createdAt": $util.dynamodb.toDynamoDBJson($time),
},
"attributeValues": $util.toJson($attribs),
"condition": {
"expression": "attribute_not_exists(#authorId) AND attribute_not_exists(#createdAt)",
"expressionNames": {
"#authorId": "authorId",
"#createdAt": "createdAt",
},
},
}
// response mapping template
$util.toJson($context.result)// request mapping template
{
"version" : "2017-02-28",
"operation" : "Query",
"index" : "authorId-index",
"query" : {
"expression": "authorId = :id",
"expressionValues" : {
":id" : {
"S" : "${ctx.source.userId}"
}
}
},
"limit": $util.defaultIfNull(${ctx.args.first}, 20),
"nextToken": $util.toJson($util.defaultIfNullOrBlank($ctx.args.after, null))
}
// response mapping template
$util.toJson($ctx.result)// request mapping template
{
"version" : "2017-02-28",
"operation" : "Query",
"index" : "followerId-index",
"query" : {
"expression": "followerId = :id",
"expressionValues" : {
":id" : {
"S" : "${ctx.source.userId}"
}
}
}
## ,
## "limit": $util.defaultIfNull(${ctx.args.first}, 20),
## "nextToken": $util.toJson($util.defaultIfNullOrBlank($ctx.args.after, null))
}
// response mapping template
## Pass back the result from DynamoDB. **
## $util.qr($util.error($ctx.result))
$util.toJson($ctx.result)// request mapping template
## UserFollowingConnection.items.request.vtl **
#set($ids = [])
#foreach($following in ${ctx.source.items})
#set($map = {})
$util.qr($map.put("userId", $util.dynamodb.toString($following.get("followerId"))))
$util.qr($ids.add($map))
#end
{
"version" : "2018-05-29",
"operation" : "BatchGetItem",
"tables" : {
"HeardUserTable": {
"keys": $util.toJson($ids),
"consistentRead": true
}
}
}
// response mapping template
## Pass back the result from DynamoDB. **
#if( ! ${ctx.result.data} )
$util.toJson([])
#else
$util.toJson($ctx.result.data.HeardUserTable)
#end
## $util.toJson($ctx.result.data.HeardUserTable)
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