In the previous article we finished building a basic web app with support for rooms, users, and password based authentication. It’s now time to deploy our app to some server. The recommended method of deployment is to generate an executable for this app, then deploy the executable, rather than deploy the source code and have Alusus itself installed on the production machine. The easiest way to do this is to use Nashir to build the app and deploy it to Alusus Net, a low cost hosting service geared towards hosting Alusus based applications. To do this, first we need to import Nashir into our app:
Apm.importFile("Alusus/Nashir", { "Nashir.alusus", "PublishDrivers/AlususNet.alusus" });
Nashir is a general building and publishing tool that can support multiple publishing targets, so we need to tell it which hosting service we are publishing on, and that’s why we are importing the AlususNet publish driver. With this imported, we can now use it in the program’s entry point. All we need to do is replace the few lines in the entry point with the following:
func initializeServer {
initializeDatabase();
}
Nashir.setup[Nashir.Config().{
projectName = "chat";
projectVersion = "v1";
serverPort = 8000;
initializer~no_deref = initializeServer~ast;
dependencies.add(Rows.PostgresqlDriver.getBuildDependencies())؛
publishDriver = Nashir.AlususNetPublishDriver();
}];
ProgArg.parse(2);
We do not need to create an entry point nor to manually start the server; Nashir will do all that for us, and it will give us the option of running the app directly, or generating an executable for it. The initializeDatabase call is now moved to a function, and that function is passed to Nashir through its config. We need to do this because we no longer want to initialize the DB directly; instead, we want the DB to be initialized by the new program entry point that will be generated automatically for us by Nashir. This will be clearer once you understand that the code at the root scope only gets executed during the JIT phase; generated executables on the other hand start from a specific function, then includes all its dependencies. This is one of the unique features of Alusus, and it allows projects to generate multiple binary builds from a single unified project, allowing Nashir in this case to generate separate builds for the front end and the back end.
The rest of the arguments in the call to Nashir.setup is pretty self explanatory, you give it the basic info of the project, the list of binary dependencies, and an instance of the publish driver to use for the actual publishing after the build is complete.
Nashir depends on a library called ProgArg, which is a library for managing program arguments. The final step is to call ProgArg.parse giving it the index from which to start parsing arguments. We start from 2 because arg 0 is alusus binary and arg 1 is the name of the source file. The call to ProgArg.parse will trigger the right action based on the user’s command line arguments.
At this poine, when you run alusus chat.alusus you will be presented with the list of commands available to you. Running alusus chat.alusus start will start the application on your machine. The build command will generate an executable, and the publish command will generate the executable then publish it on Alusus Net. The remaining publishing steps will happen interactively in the terminal, where you will be asked to enter credentials for the account that you can create on https://alusus.net, select payment options and accept terms of service, then the publishing will start and your app will be available online within minutes under a subdomain of alusus.net, with HTTPS automatically enabled. In order to let the app connect to the DB within the container you’ll need to connect using the system user rather than a Postgres user, which means setting your DB connection params as follows:
- DB name: “root”
- DB user: “root”
- DB password: “”
- DB host: “”
- DB port: 0
You can either update the code so that it defaults to these values, or keep it as is and set these values as env vars from the Alusus Net dashboard, which is the recommended approach. Notice that Alusus Net won’t let you add an env var with a value of “”, so instead use a space string, i.e. " " and this will be trimmed in the getDbDriver function. Once you set these env vars in the dashboard make sure to restart the container to let the app pick those new values. The container will take 15 seconds or so to start up after which the app will be ready for use and you can now create rooms and chat with your friends across the world.
Here is how the final source code of our app looks:
import "Srl/String";
import "Srl/Time";
import "Apm";
Apm.importFile("Alusus/Rows", { "Rows.alusus", "Drivers/Postgresql.alusus" });
Apm.importFile("Alusus/WebPlatform");
Apm.importFile("Alusus/Json");
Apm.importFile("Alusus/Nashir", { "Nashir.alusus", "PublishDrivers/AlususNet.alusus" });
use Srl;
use WebPlatform;
use Promises;
//==============================================================================
// Database
macro envVarOrDefault[varName, defaultVal] CharsPtr().{
this = System.getEnv(varName);
if this == 0 this = defaultVal;
}
@model["rooms", 1]
class RoomModel {
Rows.define_model_essentials[];
@VarChar["256"]
@primaryKey
@column
def name: String;
@VarChar["1024"]
@notNull
@column
def password: String;
}
@model["users", 1]
class UserModel {
Rows.define_model_essentials[];
@VarChar["256"]
@primaryKey
@column
def username: String;
@VarChar["1024"]
@notNull
@column
def password: String;
}
@model["messages", 2]
class MessageModel {
Rows.define_model_essentials[];
@foreignKey["rooms", "name"]
@VarChar["256"]
@notNull
@column["room_name"]
def roomName: String;
@foreignKey["users", "username"]
@VarChar["256"]
@notNull
@column
def username: String;
@VarChar["1024"]
@notNull
@column
def message: String;
@BigInteger
@notNull
@column["creation_date"]
def creationDate: Int[64];
@migration[1, 2, { RoomModel: 1; UserModel: 1 }]
function migrateToV2(db: ref[Rows.Db]): SrdRef[Error] {
db.exec("alter table messages add column room_name varchar(256) not null references rooms(name)");
db.exec("alter table messages add column username varchar(256) not null references users(username)");
return SrdRef[Error]();
}
}
def db: Rows.Db;
def schema: {
RoomModel,
UserModel,
MessageModel
};
function initializeDatabase {
db.init(closure(d: ref[SrdRef[Rows.Driver]]) {
d = getDbDriver();
});
db.schemaBuilder[schema].migrate();
}
function getDbDriver(): SrdRef[Rows.Driver] {
def driver: SrdRef[Rows.Driver] = Rows.PostgresqlDriver(Rows.ConnectionParams().{
dbName = String(envVarOrDefault["CHAT_DB_NAME", "alusus"]).trim();
userName = String(envVarOrDefault["CHAT_DB_USERNAME", "alusus"]).trim();
password = String(envVarOrDefault["CHAT_DB_PASSWORD", "alusus"]).trim();
host = String(envVarOrDefault["CHAT_DB_HOST", "0.0.0.0"]).trim();
port = String.parseInt(envVarOrDefault["CHAT_DB_PORT", "5432"]);
});
if !driver.isConnected() {
System.fail(1, String("Error connecting to DB: ") + driver.getLastError());
}
return driver;
}
//==============================================================================
// Backend
def MAX_MESSAGES: 12;
@beEndpoint["POST", "/validate-creds"]
func validateCreds (conn: ptr[Http.Connection]) {
def postData: array[Char, 1024];
def postDataSize: Int = Http.read(conn, postData~ptr, postData~size);
def body: Json = String(postData~ptr, postDataSize);
def roomName: String = body("roomName")~cast[String].trim();
def roomPassword: String = body("roomPassword");
def userName: String = body("userName")~cast[String].trim();
def userPassword: String = body("userPassword");
// Verify or create user.
def users: Array[SrdRef[UserModel]] = db.from[UserModel].where[username == userName].select();
if users.getLength() == 0 {
db.save[UserModel](UserModel().{
username = userName;
password = userPassword;
});
} else if users(0).password != userPassword {
Http.print(conn, "HTTP/1.1 401 Unauthorized\r\n\r\n");
return;
}
// Verify or create room.
def rooms: Array[SrdRef[RoomModel]] = db.from[RoomModel].where[name == roomName].select();
if rooms.getLength() == 0 {
db.save[RoomModel](RoomModel().{
name = roomName;
password = roomPassword;
});
} else if rooms(0).password != roomPassword {
Http.print(conn, "HTTP/1.1 401 Unauthorized\r\n\r\n");
return;
}
// Successful
Http.print(conn, "HTTP/1.1 200 Ok\r\n\r\n");
}
@beEndpoint["POST", "/add-message"]
func postMessages (conn: ptr[Http.Connection]) {
def postData: array[Char, 4096];
def postDataSize: Int = Http.read(conn, postData~ptr, postData~size);
def body: Json = String(postData~ptr, postDataSize);
if not validateCreds(body) {
Http.print(conn, "HTTP/1.1 401 Unauthorized\r\n\r\n");
return;
}
def msg: MessageModel;
msg.username = body("userName")~cast[String].trim();
msg.roomName = body("roomName")~cast[String].trim();
msg.message = body("message");
msg.creationDate = Time.getTimestamp(0);
db.save[MessageModel](msg);
Http.print(conn, "HTTP/1.1 200 Ok\r\n\r\n");
}
@beEndpoint["POST", "/get-messages"]
func getMessages (conn: ptr[Http.Connection]) {
def postData: array[Char, 4096];
def postDataSize: Int = Http.read(conn, postData~ptr, postData~size);
def body: Json = String(postData~ptr, postDataSize);
if not validateCreds(body) {
Http.print(conn, "HTTP/1.1 401 Unauthorized\r\n\r\n");
return;
}
// Fetch messages from DB.
def messages: Array[SrdRef[MessageModel]] = db
.from[MessageModel]
.where[roomName == body("roomName")~cast[String].trim()]
.order[-creationDate]
.select()
.slice(0, MAX_MESSAGES);
def response: StringBuilder(1024 * 10, 1024 * 5);
def i: Int;
for i = messages.getLength() - 1, i >= 0, --i {
if i != messages.getLength() - 1 response += "\n";
response.format("- %s: %s", messages(i).username.buf, messages(i).message.buf);
}
// Delete older messages.
if messages.getLength() > 0 {
db.from[MessageModel]
.where[roomName == body("roomName")~cast[String].trim() and
creationDate < messages(messages.getLength() - 1).creationDate]
.delete();
}
// Send response.
Http.print(conn, "HTTP/1.1 200 Ok\r\n");
Http.print(conn, "Content-Type: text/plain\r\n");
Http.print(conn, "Cache-Control: no-cache\r\n");
Http.print(conn, "Content-Length: %d\r\n\r\n", response.getLength());
Http.print(conn, response);
}
func validateCreds (json: Json): Bool {
def roomName: String = json("roomName")~cast[String].trim();
def roomPassword: String = json("roomPassword");
def userName: String = json("userName")~cast[String].trim();
def userPassword: String = json("userPassword");
def users: Array[SrdRef[UserModel]] = db.from[UserModel].where[username == userName].select();
if users.getLength() == 0 or users(0).password != userPassword {
return false;
}
def rooms: Array[SrdRef[RoomModel]] = db.from[RoomModel].where[name == roomName].select();
if rooms.getLength() == 0 or rooms(0).password != roomPassword {
return false;
}
return true;
}
//==============================================================================
// Frontend Components
class Header {
@injection def component: Component;
handler this~init() {
this.view = Box({}).{
style.{
padding = Length4.pt(4);
borderWidth = Length4.pt(0, 0, 1.5, 0);
borderStyle = BorderStyle.SOLID;
borderColor = Color("000");
justify = Justify.START;
display = Display.FLEX;
layout = Layout.COLUMN;
background = Background(Color("fff"));
};
addChildren({
Text(String("Wasm Chat")).{
style.fontSize = Length.pt(18.0);
}
});
};
}
handler this_type(): SrdRef[Header] {
return SrdRef[Header].construct();
}
}
class TextEntry {
@injection def component: Component;
def onNewEntry: closure (String);
def textInput: SrdRef[TextInput];
handler this~init() {
def self: ref[this_type](this);
this.view = Box({}).{
style.{
display = Display.FLEX;
layout = Layout.ROW;
justify = Justify.SPACE_BETWEEN;
};
addChildren({
TextInput().{
self.textInput = this;
style.{
flex = Flex(1);
margin = Length4.px(10);
height = Length.px(50);
fontSize = Length.pt(12.0);
borderStyle = BorderStyle.SOLID;
borderColor = Color("000");
borderWidth = Length4.px(1.5);
};
onKeyUp.connect(closure (widget: ref[TextInput], payload: ref[String]) {
if payload == "Shift+Enter" {
def newData: String = widget.getText().trim();
widget.setText(String());
if not self.onNewEntry.isNull() self.onNewEntry(newData);
}
});
},
Button(String("Send")).{
style.{
height = Length.px(50);
width = Length.px(50);
fontSize = Length.px(16.0);
justify = Justify.CENTER;
margin = Length4.px(10, 10, 10, 0);
};
onClick.connect(closure (widget: ref[Widget], payload: ref[Int]) {
def newData: String = self.textInput.getText().trim();
self.textInput.setText(String());
if not self.onNewEntry.isNull() self.onNewEntry(newData);
});
}
});
};
}
handler this_type(): SrdRef[TextEntry] {
return SrdRef[TextEntry].construct();
}
}
//==============================================================================
// Frontend Pages
def userName: String;
def userPassword: String;
def roomName: String;
def roomPassword: String;
func login {
def success: SrdRef[Promise[Int]] = Promise[Int].new();
def notification: SrdRef[Text];
def roomName: SrdRef[Input];
def roomPassword: SrdRef[Input];
def userName: SrdRef[Input];
def userPassword: SrdRef[Input];
Window.instance.setView(Box().{
style.{
height = Length.percent(100);
height = Length.percent(100);
display = Display.FLEX;
layout = Layout.COLUMN;
justify = Justify.CENTER;
align = Align.CENTER;
};
addChildren({
Text().{
notification = this;
style.{
margin = Length4.px(10);
fontColor = Color("f00");
};
},
Input().{
userName = this;
style.margin = Length4.px(10);
placeholder = String("Username");
},
Input().{
userPassword = this;
style.margin = Length4.px(10);
placeholder = String("Password");
},
Input().{
roomName = this;
style.margin = Length4.px(10);
placeholder = String("Room Name");
},
Input().{
roomPassword = this;
style.margin = Length4.px(10);
placeholder = String("Room Secret");
},
Button(String("Submit")).{
style.margin = Length4.px(10);
onClick.connect(closure (widget: ref[Widget], payload: ref[Int]) {
notification.setText(String());
def json: StringBuilder[JsonStringBuilderMixin](1024, 1025);
json.format(
"{ \"userName\": %js, \"userPassword\": %js, \"roomName\": %js, \"roomPassword\": %js }",
userName.getText().trim(),
userPassword.getText(),
roomName.getText().trim(),
roomPassword.getText()
);
sendRequest(
"POST", "/validate-creds", "Content-Type: application/text", json, 10000,
closure (json: Json) {
def status: Int = json("eventData")("status");
if status == 200 {
Root.userName = userName.getText().trim();
Root.userPassword = userPassword.getText();
Root.roomName = roomName.getText().trim();
Root.roomPassword = roomPassword.getText();
success.resolve(0);
} else {
notification.setText(String("Login failed!"));
}
}
);
});
}
});
});
await(success);
}
@uiEndpoint["/"]
@title["Wasm Chat"]
func main {
def onFetch: closure (json: Json);
Window.instance.style.{
padding = Length4.pt(0);
margin = Length4.pt(0);
};
login();
def getMessagesJson: String = StringBuilder[JsonStringBuilderMixin](1024, 1025).{
format(
"{ \"userName\": %js, \"userPassword\": %js, \"roomName\": %js, \"roomPassword\": %js }",
userName, userPassword, roomName, roomPassword
);
};
Window.instance.setView(Box({}).{
style.{
height = Length.percent(100);
justify = Justify.SPACE_BETWEEN;
display = Display.FLEX;
layout = Layout.COLUMN;
background = Background(Color("aaa"));
};
addChildren({
Header(),
Text(String()).{
style.{
flex = Flex(1);
width = Length.percent(100) - Length.px(20);
margin = Length4.px(10, 10, 0, 10);
fontSize = Length.pt(20.0);
borderStyle = BorderStyle.SOLID;
borderColor = Color("000");
borderWidth = Length4.px(1.5);
background = Background(Color("fff"));
};
onFetch = closure (json: Json) {
def status: Int[64] = json("eventData")("status");
if status >= 200 and status < 300 {
def data: String = json("eventData")("body");
if this.getText() != data {
this.setText(data);
}
}
};
},
TextEntry().{
onNewEntry = closure (newData: String) {
def postMessagesJson: StringBuilder[JsonStringBuilderMixin](1024, 1025);
postMessagesJson.format(
"{ \"userName\": %js, \"userPassword\": %js, \"roomName\": %js, \"roomPassword\": %js, \"message\": %js }",
userName, userPassword, roomName, roomPassword, newData
);
sendRequest(
"POST", "/add-message", "Content-Type: application/json", postMessagesJson, 10000,
closure (Json) {
sendRequest("POST", "/get-messages", "Content-Type: application/json", getMessagesJson, 500, onFetch);
}
);
};
};
})
});
startTimer(500000, closure (json: Json) {
sendRequest("POST", "/get-messages", "Content-Type: application/json", getMessagesJson, 500, onFetch);
});
sendRequest("POST", "/get-messages", "Content-Type: application/json", getMessagesJson, 500, onFetch);
runEventLoop();
}
//==============================================================================
// Entry Point
func initializeServer {
initializeDatabase();
}
Nashir.setup[Nashir.Config().{
projectName = "chat";
projectVersion = "v1";
serverPort = 8000;
initializer~no_deref = initializeServer~ast;
dependencies.add(Rows.PostgresqlDriver.getBuildDependencies())؛
publishDriver = Nashir.AlususNetPublishDriver();
}];
ProgArg.parse(2);
Stay tuned for upcoming articles where I will be explaining in more details what happens behind the scenes in this app, and what makes Alusus programming language a truely unique and promising programming language.