From d58f0cc39bb9759ebd46d7a871af37f63e64ccaa Mon Sep 17 00:00:00 2001
From: Dave Longley <dlongley@digitalbazaar.com>
Date: Tue, 28 Jan 2025 00:06:37 -0500
Subject: [PATCH] JSON-encode exchange variables if they include illegal
 mongodb key chars.

---
 CHANGELOG.md     |  6 ++++++
 lib/exchanges.js | 56 ++++++++++++++++++++++++++++++++++++++++++------
 2 files changed, 55 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index c06b4da..26e00a2 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,11 @@
 # bedrock-vc-delivery ChangeLog
 
+## 6.5.0 - 2025-01-dd
+
+### Added
+- Allow exchange variables to contain JSON key values that are not
+  supported in mongoDB.
+
 ## 6.4.1 - 2025-01-27
 
 ### Fixed
diff --git a/lib/exchanges.js b/lib/exchanges.js
index ca8fdb8..625c31a 100644
--- a/lib/exchanges.js
+++ b/lib/exchanges.js
@@ -1,5 +1,5 @@
 /*!
- * Copyright (c) 2022-2024 Digital Bazaar, Inc. All rights reserved.
+ * Copyright (c) 2022-2025 Digital Bazaar, Inc. All rights reserved.
  */
 import * as bedrock from '@bedrock/core';
 import * as database from '@bedrock/mongodb';
@@ -35,6 +35,8 @@ const LAST_ERROR_UPDATE_CONSTRAINTS = {
   updateTimeLimit: 1000
 };
 
+const MONGODB_ILLEGAL_KEY_CHAR_REGEX = /[%$.]/;
+
 bedrock.events.on('bedrock-mongodb.ready', async () => {
   await database.openCollections([COLLECTION_NAME]);
 
@@ -110,14 +112,14 @@ export async function insert({workflowId, exchange}) {
     // backwards compatibility: enable existing systems to find record
     localExchangerId: localWorkflowId,
     meta,
-    exchange
+    exchange: _encodeVariables({exchange})
   };
 
   // insert the exchange and get the updated record
   try {
     const collection = database.collections[COLLECTION_NAME];
-    const result = await collection.insertOne(record);
-    return result.ops[0];
+    await collection.insertOne(record);
+    return record;
   } catch(e) {
     if(!database.isDuplicateError(e)) {
       throw e;
@@ -199,6 +201,8 @@ export async function get({
     });
   }
 
+  record.exchange = _decodeVariables({exchange: record.exchange});
+
   // backwards compatibility; initialize `sequence`
   if(record.exchange.sequence === undefined) {
     const query = {
@@ -237,6 +241,9 @@ export async function update({workflowId, exchange, explain = false} = {}) {
   assert.object(exchange, 'exchange');
   const {id} = exchange;
 
+  // encode variable content for storage in mongoDB
+  exchange = _encodeVariables({exchange});
+
   // build update
   const update = _buildUpdate({exchange, complete: false});
 
@@ -566,13 +573,13 @@ function _buildUpdate({exchange, complete}) {
     $set: {'exchange.state': exchange.state, 'meta.updated': now},
     $unset: {}
   };
-  if(complete) {
-    // exchange complete, only update results
+  if(complete && typeof exchange.variables !== 'string') {
+    // exchange complete and variables not encoded, so only update results
     if(exchange.variables?.results) {
       update.$set['exchange.variables.results'] = exchange.variables.results;
     }
   } else {
-    // exchange not complete, update all variables
+    // exchange not complete or variables are encoded, so update all variables
     if(exchange.variables) {
       update.$set['exchange.variables'] = exchange.variables;
     }
@@ -600,6 +607,41 @@ function _buildUpdate({exchange, complete}) {
   return update;
 }
 
+function _encodeVariables({exchange}) {
+  // if any JSON object any variable uses a character that is not legal in
+  // a JSON key in mongoDB then stringify all the variables
+  if(_hasIllegalMongoDBKeyChar(exchange.variables)) {
+    return {...exchange, variables: JSON.stringify(exchange.variables)};
+  }
+  return exchange;
+}
+
+function _decodeVariables({exchange}) {
+  if(typeof exchange.variables === 'string') {
+    return {...exchange, variables: JSON.parse(exchange.variables)};
+  }
+  return exchange;
+}
+
+function _hasIllegalMongoDBKeyChar(value) {
+  if(Array.isArray(value)) {
+    for(const e of value) {
+      if(_hasIllegalMongoDBKeyChar(e)) {
+        return true;
+      }
+    }
+  } else if(value && typeof value === 'object') {
+    const keys = Object.keys(value);
+    for(const key of keys) {
+      if(MONGODB_ILLEGAL_KEY_CHAR_REGEX.test(key) ||
+        _hasIllegalMongoDBKeyChar(value[key])) {
+        return true;
+      }
+    }
+  }
+  return false;
+}
+
 /**
  * An object containing information on the query plan.
  *