From 4691e2f084990b4987d39cfc158b53f417280616 Mon Sep 17 00:00:00 2001
From: Yaroslav Pshenichnikov <yaroslav.pshenichnikov@onlyoffice.com>
Date: Tue, 30 Jul 2024 13:24:40 +0300
Subject: [PATCH] Add first version of zoom reverse proxy

---
 develop-template.yaml        | 23 +++++++++++
 zoom-reverse-proxy/index.mjs | 80 ++++++++++++++++++++++++++++++++++++
 2 files changed, 103 insertions(+)
 create mode 100644 zoom-reverse-proxy/index.mjs

diff --git a/develop-template.yaml b/develop-template.yaml
index 0ce978d..30959d5 100644
--- a/develop-template.yaml
+++ b/develop-template.yaml
@@ -53,6 +53,29 @@ Resources:
         ApplyOn: None
       PackageType: Zip
       Role: !GetAtt DocspaceReverseProxyRole.Arn
+    
+  zoomreverseproxy:
+    Type: AWS::Serverless::Function
+    Properties:
+      CodeUri: zoom-reverse-proxy/
+      Description: ""
+      MemorySize: 128
+      Timeout: 3
+      Handler: index.handler
+      Runtime: nodejs18.x
+      Architectures:
+        - x86_64
+      EventInvokeConfig:
+        MaximumEventAgeInSeconds: 21600
+        MaximumRetryAttempts: 2
+      EphemeralStorage:
+        Size: 512
+      RuntimeManagementConfig:
+        UpdateRuntimeOn: Auto
+      SnapStart:
+        ApplyOn: None
+      PackageType: Zip
+      Role: !GetAtt DocspaceReverseProxyRole.Arn
 
   GlobalDynamoDBTable:
     Type: AWS::DynamoDB::GlobalTable
diff --git a/zoom-reverse-proxy/index.mjs b/zoom-reverse-proxy/index.mjs
new file mode 100644
index 0000000..88964eb
--- /dev/null
+++ b/zoom-reverse-proxy/index.mjs
@@ -0,0 +1,80 @@
+'use strict';
+
+const AWS = require('aws-sdk');
+const cachedItem = {};
+const regionsMap = {
+  'us-west-2': 'oforms.onlyoffice.com',
+  'eu-central-1': 'blog.onlyoffice.com',
+  'default': 'onlyoffice.com'
+};
+
+const ddbRegionsMap = {
+    ddbRegionsMap_placeholder
+};
+
+const dynamodbTableName = "dynamodb_table_name_placeholder";
+
+const execRegionCode = process.env.AWS_REGION;
+var ddbClientRegion = ddbRegionsMap[execRegionCode] || ddbRegionsMap["default"];
+
+console.log("DynamoDB client region set to: %s", ddbClientRegion);
+
+const { DynamoDBClient, GetItemCommand } = require("@aws-sdk/client-dynamodb");
+
+async function getTenantRegion(ddbRegion, tenantDomain) {
+  console.log("Fetching tenant region for domain: %s from DynamoDB region: %s", tenantDomain, ddbRegion);
+  const ddbClient = new DynamoDBClient({ region: ddbRegion });
+  const getItemParams = {
+    Key: { 'tenant_domain': { S: tenantDomain } },
+    ProjectionExpression: "tenant_region",
+    TableName: dynamodbTableName
+  };
+
+  try {
+    const response = await ddbClient.send(new GetItemCommand(getItemParams));
+    if (response.Item) {
+      const tenantRegion = regionsMap[response.Item["tenant_region"]["S"]];
+      console.log("Tenant region fetched: %s", tenantRegion);
+      return tenantRegion;
+    } else {
+      console.warn("No data found for domain: %s", tenantDomain);
+      return null;
+    }
+  } catch (err) {
+    console.error("Error fetching from DynamoDB: %s", err);
+    return null;
+  }
+}
+
+exports.handler = async (event) => {
+  const request = event.Records[0].cf.request;
+  const headers = request.headers;
+  const fullDomain = headers.host[0].value.toLowerCase();
+  const domainParts = fullDomain.split('.');
+
+  if (domainParts.length === 4 && domainParts[1] === 'devops' && domainParts[2] === 'onlyoffice' && domainParts[3] === 'io') {
+    const tenantDomain = fullDomain;
+
+    // Check the cache first
+    if (cachedItem[tenantDomain] && cachedItem[tenantDomain].expiresOn > Date.now()) {
+      request.origin.custom.domainName = cachedItem[tenantDomain].value;
+      console.log("Origin fetched from cache for domain: %s", tenantDomain);
+    } else {
+      // Fetch the region from DynamoDB and update the origin
+      const tenantRegion = await getTenantRegion(ddbClientRegion, tenantDomain);
+      if (tenantRegion) {
+        request.origin.custom.domainName = tenantRegion;
+        cachedItem[tenantDomain] = {
+          value: tenantRegion,
+          expiresOn: Date.now() + 15 * 60 * 1000 // Cache for 15 minutes
+        };
+        console.log("Origin updated to %s for domain: %s", tenantRegion, tenantDomain);
+      } else {
+        request.origin.custom.domainName = regionsMap["default"];
+        console.log("Default origin used for domain: %s", tenantDomain);
+      }
+    }
+  }
+
+  return request;
+};