Module 14: Creating a WhatsApp Clone
Transcript
the next step is the services layer which implements the relatively simple business layer of this application we’ll start with the user service class it’s the main class in this package and handles pretty much the entire business logic of the app it’s a service bean this means it handles generic business logic for the application we need access to the repositories we just defined for users groups and messages the api keys service is the exact one i used in facebook with the exception of a different properties file name i’ll discuss that later it generally abstracts api keys and separates them from the source code the password encoder is used to encrypt and verify the token media repository and notification servers are identical to the stuff we had in the facebook clone app this method sends an sms message via the twillow web service if you recall we added the twillow sdk into the pom file in the first lesson this sdk makes sending an sms message very easy as you can see from the code the login api lets us validate a user and get the current data the server has for that user since there is no username slash password we need to use the token to authenticate first we need to find the user with the given phone assuming the user isn’t there will throw an exception since the auth is hashed as we discussed before we need to test the incoming auth via the matches method in encoder it verifies the hash matches the auth token this method creates a string of the given length which includes a random number for verification signup creates an entry for a specific user but doesn’t activate the account until it’s verified we first check if the phone number is already registered if so we need to fail otherwise we create the new user and initialize the value of the data and the verification code finally we send the activation code and return the user entity the verify method activates a user account if the verification mode is correct we mark the user as verified and return true we use set props both from the sign up and update methods there isn’t much here but if we add additional metadata this might become a bigger method like it is and the facebook clone update verifies the user’s token then updates the properties there isn’t much here these aren’t used at the moment but they are pretty much identical to what we have in the facebook clone and should be easy to integrate in a similar way this is part of the work to integrate support for the user typing feature right now the client app doesn’t send or render this event but it should be relatively simple to add when a user starts typing to a conversation we can invoke this method two user can be a user or a group is the user present it’s if the user is present it’s a user i’ll discuss the event code in the sockets when we reach the app socket class and this if this is a group we need to send the event to all the users within the group via the socket connection this method sends a message to its destination which can be a user or a group in order to send a message we first need to create a chat entity message entity so we can persist the message in case delivery failed this is the same code we saw in the typing event if the message is destined to a user the following block will occur otherwise we’ll go to the else block where the exact same code will execute in a loop over the members of the group we mark the destination of the message and convert it to json to adjacent string we invoke the send message api the send message uses the socket to send the message to the device if this failed and the device isn’t reachable we should send this message as text using push notification this method is identical to the other send message method but it uses a json string which is more convenient when a message comes in through the websocket the previous version is the one used when this is invoked from the web service which is what we use and this one works when a message is sent via the websocket this method converts a chat message entity to json so we can send it to the client object mapper can convert a pojo object to the equivalent json string this method sends json via the socket to the group or a user it allows us to propagate a message onward it works pretty much like the other methods in this class that send to a group or a user this method finds the user matching the given phone number this method is used by find registered user and find registered user by id it generalizes that translation of a user list to a single user dial value it implicitly fails for unverified users as well ack allows us to acknowledge that a message was received it just toggles the ack flag when a user connects via websocket this method is invoked it finds all the messages that weren’t act by the user and sends them to that user that way if a device lost connection it will get the content once it’s back online this method is invoked on launch to update the push key in the server so we can send push messages to the device with that user service is finished