Add Server-Sent Events BBE

examples/http-sse-client/http_sse_client.bal

@@ -0,0 +1,11 @@
+import ballerina/http;
+import ballerina/io;
+
+public function main() returns error? {
+    http:Client clientEp = check new ("localhost:9090");
+    stream<http:SseEvent, error?> eventStream = check clientEp->/stocks;
+    check from http:SseEvent event in eventStream
+        do {
+            io:println("Stock price: ", event.data);
+        };
+}

examples/http-sse-client/http_sse_client.client.out

@@ -0,0 +1,7 @@
+$ bal run http_sse_client.bal
+
+Stock price: 249.9963321685791
+Stock price: 56.58070945739746
+Stock price: 571.2127494812012
+Stock price: 217.98820853233337
+Stock price: 21.891758739948273

examples/http-sse-client/http_sse_client.md

@@ -0,0 +1,16 @@
+# HTTP client - Server-sent events
+
+The `http:Client` in Ballerina supports receiving real-time data from services using Server-sent events (SSE). It allows payload-binding of a stream of `http:SseEvent` when consuming SSE from a service. This payload binding fails if the content type header is not present in the response or does not have the value `text/event-stream`.
+
+::: code http_sse_client.bal :::
+
+## Prerequisites
+- Run the HTTP service given in the [Server-sent events](/learn/by-example/http-sse-service/) example.
+
+Run the client program by executing the following command.
+
+::: out http_sse_client.client.out :::
+
+## Related links
+- [`http` module - API documentation](https://lib.ballerina.io/ballerina/http/latest/)
+- [Client action return types - Specification](/spec/http/#243-client-action-return-types)

examples/http-sse-client/http_sse_client.metatags

@@ -0,0 +1,2 @@
+description: This example demonstrates how Server-sent events (SSE) can be consumed using an HTTP client.
+keywords: ballerina, ballerina by example, bbe, http, SSE, client

examples/http-sse-service/http_sse_service.bal

@@ -0,0 +1,31 @@
+import ballerina/http;
+import ballerina/lang.runtime;
+import ballerina/random;
+
+service /stocks on new http:Listener(9090) {
+    // This function returns a stream of SSE with stock prices
+    resource function get .() returns stream<http:SseEvent, error?> {
+        // Create a new instance of StockPriceEventGenerator to generate stock price events
+        StockPriceEventGenerator generator = new;
+        // Return a new stream that uses the generator to produce events
+        return new (generator);
+    }
+}
+
+// Define a class to generate stock price events
+class StockPriceEventGenerator {
+    int eventCounter = 0;
+
+    public isolated function next() returns record {|http:SseEvent value;|}|error? {
+        // If the eventCounter reaches 5, stop generating events by returning nil
+        if self.eventCounter == 5 {
+            return ();
+        }
+        self.eventCounter += 1;
+        runtime:sleep(1);
+        // Generate a random stock price
+        float stockPrice = (check random:createIntInRange(1, 1000)) * random:createDecimal();
+        http:SseEvent event = {data: stockPrice.toString()};
+        return {value: event};
+    }
+}

examples/http-sse-service/http_sse_service.client.out

@@ -0,0 +1,27 @@
+$ curl -v localhost:9090/stocks
+*   Trying [::1]:9090...
+* Connected to localhost (::1) port 9090
+> GET /stocks/stockA HTTP/1.1
+> Host: localhost:9090
+> User-Agent: curl/8.4.0
+> Accept: */*
+> 
+< HTTP/1.1 200 OK
+< content-type: text/event-stream
+< cache-control: no-cache,public
+< transfer-encoding: chunked
+< connection: keep-alive
+< server: ballerina
+< date: Fri, 2 Aug 2024 12:02:04 +0530
+< 
+data: 76.6014928817749
+
+data: 789.1765828132629
+
+data: 241.89215344190598
+
+data: 494.8120536804199
+
+data: 234.36854779720306
+
+* Connection #0 to host localhost left intact

examples/http-sse-service/http_sse_service.md

@@ -0,0 +1,17 @@
+# HTTP service - Server-sent events
+
+Ballerina HTTP services support pushing real-time data to clients using Server-event events (SSE). A stream of type `http:SseEvent` can be returned from service resource methods. This feature automatically handles sending SSE and sets the content type to `text/event-stream` and the transfer encoding to chunked.
+
+::: code http_sse_service.bal :::
+
+Run the service program by executing the following command.
+
+::: out http_sse_service.server.out :::
+
+Invoke the service by executing the following cURL command in a new terminal.
+
+::: out http_sse_service.client.out :::
+
+## Related links
+- [`http` module - API documentation](https://lib.ballerina.io/ballerina/http/latest/)
+- [Resource return types - Specification](/spec/http/#235-return-types)

examples/http-sse-service/http_sse_service.metatags

@@ -0,0 +1,2 @@
+description: This example demonstrates how Server-sent events (SSE) can be produced using an HTTP service.
+keywords: ballerina, ballerina by example, bbe, http, SSE, service

examples/http-sse-service/http_sse_service.server.out

@@ -0,0 +1 @@
+$ bal run http_sse_service.bal

examples/index.json

@@ -2256,6 +2256,14 @@
         "verifyOutput": false,
         "disablePlayground": false,
         "isLearnByExample": false
+      },
+      {
+        "name": "Server-sent events",
+        "url": "http-sse-service",
+        "verifyBuild": true,
+        "verifyOutput": false,
+        "disablePlayground": false,
+        "isLearnByExample": false
       }
     ]
   },
@@ -2327,6 +2335,14 @@
         "verifyOutput": false,
         "disablePlayground": false,
         "isLearnByExample": false
+      },
+      {
+        "name": "Server-sent events",
+        "url": "http-sse-client",
+        "verifyBuild": true,
+        "verifyOutput": false,
+        "disablePlayground": false,
+        "isLearnByExample": false
       }
     ]
   },

gradle.properties

@@ -25,7 +25,7 @@ stdlibMathVectorVersion=1.0.2
 # Stdlib Level 02
 stdlibAvroVersion=1.0.0
 stdlibConstraintVersion=1.5.0
-stdlibCryptoVersion=2.7.0
+stdlibCryptoVersion=2.7.2
 stdlibDataXmldataVersion=0.1.4
 stdlibLogVersion=2.9.0
 stdlibOsVersion=1.8.0
@@ -40,7 +40,7 @@ observeInternalVersion=1.2.2
 stdlibCacheVersion=3.8.0
 stdlibFileVersion=1.9.0
 stdlibFtpVersion=2.10.1
-stdlibMimeVersion=2.9.0
+stdlibMimeVersion=2.10.0-20240724-124600-f193322
 stdlibTcpVersion=1.10.0
 stdlibUdpVersion=1.10.0
 stdlibUuidVersion=1.8.0
@@ -50,14 +50,14 @@ stdlibAuthVersion=2.11.0
 stdlibDataJsondataVersion=0.1.0
 stdlibEdiVersion=1.2.0
 stdlibEmailVersion=2.9.0
-stdlibJwtVersion=2.11.0
+stdlibJwtVersion=2.12.1
 stdlibMqttVersion=1.1.1
 stdlibOAuth2Version=2.11.0
 stdlibTomlVersion=0.5.1
 stdlibYamlVersion=0.5.3
 
 # Stdlib Level 05
-stdlibHttpVersion=2.11.1
+stdlibHttpVersion=2.12.0-20240801-081400-0b676d6
 
 # Stdlib Level 06
 stdlibGrpcVersion=1.11.1