Create callback endpoint

platform/src/main/java/com/flickmatch/platform/graphql/controller/PaymentController.java

@@ -32,6 +32,11 @@ public InitiatePaymentOutput initiatePayment(@Argument InitiatePaymentInput inpu
         return output;
     }
 
+    /*
+    Calls PhonePe Pay API using sdk
+    https://developer.phonepe.com/v1/reference/pay-api-1
+    https://developer.phonepe.com/v1/reference/java-standard-pay-page
+     */
     private String initiate() {
         String merchantId = "M1FPXNBFIGDG";
         String saltKey = "e7a5693b-0ccf-47ac-a258-c5d77e701e2c";
@@ -42,14 +47,14 @@ private String initiate() {
 
         String merchantTransactionId = UUID.randomUUID().toString().substring(0,34);
         long amount = 200;
-        String callbackurl = "https://www.merchant.com/callback";
+        String callbackUrl = "https://service.flickmatch.in:8443/platform-0.0.1-SNAPSHOT/payment";
         String merchantUserId = "merchantUserId";
 
         PgPayRequest pgPayRequest = PgPayRequest.PayPagePayRequestBuilder()
                 .amount(amount)
                 .merchantId(merchantId)
                 .merchantTransactionId(merchantTransactionId)
-                .callbackUrl(callbackurl)
+                .callbackUrl(callbackUrl)
                 .callbackMode("REDIRECT")
                 .redirectUrl("https://play.flickmatch.in/")
                 .redirectMode("REDIRECT")

platform/src/main/java/com/flickmatch/platform/rest/CallBackResponse.java

@@ -0,0 +1,8 @@
+package com.flickmatch.platform.rest;
+
+import lombok.Data;
+
+@Data
+public class CallBackResponse {
+    private String response;
+}

platform/src/main/java/com/flickmatch/platform/rest/PhonePeCallBackController.java

@@ -0,0 +1,37 @@
+package com.flickmatch.platform.rest;
+
+import lombok.extern.log4j.Log4j2;
+import org.springframework.boot.json.GsonJsonParser;
+import org.springframework.boot.json.JacksonJsonParser;
+import org.springframework.boot.json.JsonParser;
+import org.springframework.web.bind.annotation.PostMapping;
+import org.springframework.web.bind.annotation.RequestBody;
+import org.springframework.web.bind.annotation.RequestHeader;
+import org.springframework.web.bind.annotation.RestController;
+
+import java.util.Base64;
+import java.util.Map;
+
+/**
+ * Exposes POST endpoint for phonepe callback.
+ * https://developer.phonepe.com/v1/reference/server-to-server-callback-5
+ */
+@RestController
+@Log4j2
+public class PhonePeCallBackController {
+
+    private static final JsonParser jsonParser = new JacksonJsonParser();
+
+    @PostMapping("/payment")
+    void processCallBack(@RequestBody CallBackResponse callBackResponse,
+                         @RequestHeader("x_verify") String xVerify) {
+        log.info(xVerify); //We need to use this to verify callback https://developer.phonepe.com/v1/reference/java-callback-verification
+        String decodedResponse = new String(Base64.getDecoder().decode(callBackResponse.getResponse()));
+        Map<String, Object> phonePeResponse = jsonParser.parseMap(decodedResponse);
+        if ("PAYMENT_SUCCESS".equals(phonePeResponse.get("code"))) {
+            log.info("store data in DB");
+        } else {
+            log.error(decodedResponse);
+        }
+    }
+}