@getanthill/event-source - npm Package Compare versions

Comparing version 0.8.0 to 0.9.0

dist/Events.js

@@ -5,3 +5,2 @@ "use strict";
 const assert_1 = require("assert");
-const date = require("./utils/date");
 /**
@@ -102,7 +101,3 @@ * Events class to manage events for EventSourced instances
     static store(collection, events) {
-        const datedEvents = events.map((event) => ({
-            created_at: date.getNow(),
-            ...event,
-        }));
-        return collection.insertMany(datedEvents);
+        return collection.insertMany(events);
     }
@@ -109,0 +104,0 @@ }

dist/EventSourced.d.ts

@@ -11,5 +11,12 @@ import * as ERRORS from './errors';
     CORRELATION_FIELD: string;
+    CREATED_AT_FIELD: string;
+    CURRENT_HASH_FIELD: string;
+    PREVIOUS_HASH_FIELD: string;
+    NONCE_FIELD: string;
     EVENTS_COLLECTION_NAME: string;
     SNAPSHOTS_COLLECTION_NAME: string;
     WITH_GLOBAL_VERSION: boolean;
+    WITH_BLOCKCHAIN_HASH: boolean;
+    BLOCKCHAIN_HASH_DIFFICULTY: number;
+    BLOCKCHAIN_HASH_GENESIS: string;
 }
@@ -22,2 +29,6 @@ /**
  * @param {string} [options.CORRELATION_FIELD='correlation_id'] The correlation id
+ * @param {string} [options.CREATED_AT_FIELD='created_at'] The event created_at field
+ * @param {string} [options.CURRENT_HASH_FIELD='hash'] The blockchain hash field
+ * @param {string} [options.PREVIOUS_HASH_FIELD='prev'] The blockchain previous hash field
+ * @param {string} [options.NONCE_FIELD='nonce'] The blockchain hash field
  * @param {string} [options.EVENTS_COLLECTION_NAME=`${collectionName}_events`]
@@ -29,2 +40,9 @@ *  The events collection name
  *  of a entity-local one
+ * @param {number} [options.BLOCKCHAIN_HASH_DIFFICULTY=0]
+ *  Blockchain hash generation difficulty
+ * @param {boolean} [options.WITH_BLOCKCHAIN_HASH=false]
+ *  Does the model have a blockchain hash generated version
+ *  after version
+ * @param {boolean} [options.BLOCKCHAIN_HASH_GENESIS=0000000000000000000000000000000000000000000000000000000000000000]
+ *  Genesis hash value
  *
@@ -143,2 +161,24 @@ *  The snapshots collection name
     /**
+     * Compute the hash for the blockchain mode
+     * @param {number} version
+     * @param {Date} createdAt
+     * @param {object} state
+     * @param {string} [precedingHash=' ']
+     * @param {number} [nonce=0]
+     * @returns {string}
+     */
+    computeHash(version: number, createdAt: Date | string, state: any, nonce: number, precedingHash: string): string;
+    /**
+     * Computes a difficult blockchain hash
+     * @param {number} version
+     * @param {Date} createdAt
+     * @param {object} state
+     * @param {string} [precedingHash]
+     * @returns {string}
+     */
+    computeDifficultHash(version: number, createdAt: Date | string, state: any, precedingHash: string): {
+        hash: string;
+        nonce: number;
+    };
+    /**
      * Reduce events on the given state
@@ -145,0 +185,0 @@ * @param {object[]} events Array of events

dist/EventSourced.js

@@ -5,2 +5,3 @@ "use strict";
 const assert_1 = require("assert");
+const crypto = require("crypto");
 const lodash_1 = require("lodash");
@@ -11,2 +12,3 @@ const deep_freeze_1 = require("./utils/deep-freeze");
 const ERRORS = require("./errors");
+const date = require("./utils/date");
 /**
@@ -18,2 +20,6 @@ * Factory of the EventSourced class
  * @param {string} [options.CORRELATION_FIELD='correlation_id'] The correlation id
+ * @param {string} [options.CREATED_AT_FIELD='created_at'] The event created_at field
+ * @param {string} [options.CURRENT_HASH_FIELD='hash'] The blockchain hash field
+ * @param {string} [options.PREVIOUS_HASH_FIELD='prev'] The blockchain previous hash field
+ * @param {string} [options.NONCE_FIELD='nonce'] The blockchain hash field
  * @param {string} [options.EVENTS_COLLECTION_NAME=`${collectionName}_events`]
@@ -25,2 +31,9 @@ *  The events collection name
  *  of a entity-local one
+ * @param {number} [options.BLOCKCHAIN_HASH_DIFFICULTY=0]
+ *  Blockchain hash generation difficulty
+ * @param {boolean} [options.WITH_BLOCKCHAIN_HASH=false]
+ *  Does the model have a blockchain hash generated version
+ *  after version
+ * @param {boolean} [options.BLOCKCHAIN_HASH_GENESIS=0000000000000000000000000000000000000000000000000000000000000000]
+ *  Genesis hash value
  *
@@ -58,5 +71,12 @@ *  The snapshots collection name
                 CORRELATION_FIELD: 'correlation_id',
+                CURRENT_HASH_FIELD: 'hash',
+                PREVIOUS_HASH_FIELD: 'prev',
+                NONCE_FIELD: 'nonce',
+                CREATED_AT_FIELD: 'created_at',
                 EVENTS_COLLECTION_NAME: `${collectionName}_events`,
                 SNAPSHOTS_COLLECTION_NAME: `${collectionName}_snapshots`,
                 WITH_GLOBAL_VERSION: false,
+                WITH_BLOCKCHAIN_HASH: false,
+                BLOCKCHAIN_HASH_DIFFICULTY: 0,
+                BLOCKCHAIN_HASH_GENESIS: '0000000000000000000000000000000000000000000000000000000000000000',
             }, options);
@@ -147,2 +167,38 @@ }
         /**
+         * Compute the hash for the blockchain mode
+         * @param {number} version
+         * @param {Date} createdAt
+         * @param {object} state
+         * @param {string} [precedingHash=' ']
+         * @param {number} [nonce=0]
+         * @returns {string}
+         */
+        static computeHash(version, createdAt, state, nonce, precedingHash) {
+            const hash = crypto.createHash('sha256');
+            hash.update(`${version}${precedingHash}${createdAt}${JSON.stringify((0, lodash_1.omit)(state, [
+                EventSourced.options.CURRENT_HASH_FIELD,
+                EventSourced.options.PREVIOUS_HASH_FIELD,
+                EventSourced.options.NONCE_FIELD,
+            ]))}${nonce}`);
+            return hash.digest('hex');
+        }
+        /**
+         * Computes a difficult blockchain hash
+         * @param {number} version
+         * @param {Date} createdAt
+         * @param {object} state
+         * @param {string} [precedingHash]
+         * @returns {string}
+         */
+        static computeDifficultHash(version, createdAt, state, precedingHash) {
+            const difficulty = EventSourced.options.BLOCKCHAIN_HASH_DIFFICULTY;
+            let nonce = 0;
+            let hash = EventSourced.computeHash(version, createdAt, state, nonce, precedingHash);
+            while (hash.substring(0, difficulty) !== Array(difficulty + 1).join('0')) {
+                nonce += 1;
+                hash = EventSourced.computeHash(version, createdAt, state, nonce, precedingHash);
+            }
+            return { hash, nonce };
+        }
+        /**
          * Reduce events on the given state
@@ -166,2 +222,9 @@ * @param {object[]} events Array of events
                 }
+                const precedingHash = (options.WITH_GLOBAL_VERSION === true && globalVersion > stateVersion
+                    ? lastEvent?.[EventSourced.options.CURRENT_HASH_FIELD]
+                    : updated?.[EventSourced.options.CURRENT_HASH_FIELD]) ||
+                    EventSourced.options.BLOCKCHAIN_HASH_GENESIS;
+                // Apply a timestamp to the event:
+                event[EventSourced.options.CREATED_AT_FIELD] =
+                    event[EventSourced.options.CREATED_AT_FIELD] || date.getNow();
                 updated = reducer(updated, event);
@@ -178,2 +241,13 @@ // Force the event version tagging
                 event[EventSourced.options.CORRELATION_FIELD] = correlationId;
+                // Blockchain logic
+                if (options.WITH_BLOCKCHAIN_HASH === true) {
+                    const { hash, nonce } = EventSourced.computeDifficultHash(event.version, event.created_at, event, precedingHash);
+                    updated[EventSourced.options.CURRENT_HASH_FIELD] = hash;
+                    updated[EventSourced.options.NONCE_FIELD] = nonce;
+                    event[EventSourced.options.PREVIOUS_HASH_FIELD] = precedingHash;
+                    event[EventSourced.options.CURRENT_HASH_FIELD] =
+                        updated[EventSourced.options.CURRENT_HASH_FIELD];
+                    event[EventSourced.options.NONCE_FIELD] =
+                        updated[EventSourced.options.NONCE_FIELD];
+                }
                 return (0, deep_freeze_1.deepFreeze)(updated);
@@ -180,0 +254,0 @@ }, (0, deep_freeze_1.deepFreeze)((0, lodash_1.cloneDeep)(state)));

package.json

 {
   "name": "@getanthill/event-source",
-  "version": "0.8.0",
+  "version": "0.9.0",
   "description": "Event-sourced data store handling library",
@@ -5,0 +5,0 @@ "main": "dist/index.js",

src/Events.ts

@@ -118,9 +118,4 @@ import { strict as assert } from 'assert';
   static store(collection, events) {
-    const datedEvents = events.map((event) => ({
-      created_at: date.getNow(),
-      ...event,
-    }));
-
-    return collection.insertMany(datedEvents);
+    return collection.insertMany(events);
   }
 }

src/EventSourced.ts

 import { strict as assert } from 'assert';
+import * as crypto from 'crypto';
 
-import { cloneDeep } from 'lodash';
+import { cloneDeep, omit } from 'lodash';
 
@@ -13,2 +14,4 @@ import { deepFreeze } from './utils/deep-freeze';
 
+import * as date from './utils/date';
+
 interface Logger {
@@ -23,5 +26,12 @@ trace: Function;
   CORRELATION_FIELD: string;
+  CREATED_AT_FIELD: string;
+  CURRENT_HASH_FIELD: string;
+  PREVIOUS_HASH_FIELD: string;
+  NONCE_FIELD: string;
   EVENTS_COLLECTION_NAME: string;
   SNAPSHOTS_COLLECTION_NAME: string;
   WITH_GLOBAL_VERSION: boolean;
+  WITH_BLOCKCHAIN_HASH: boolean;
+  BLOCKCHAIN_HASH_DIFFICULTY: number;
+  BLOCKCHAIN_HASH_GENESIS: string;
 }
@@ -35,2 +45,6 @@
  * @param {string} [options.CORRELATION_FIELD='correlation_id'] The correlation id
+ * @param {string} [options.CREATED_AT_FIELD='created_at'] The event created_at field
+ * @param {string} [options.CURRENT_HASH_FIELD='hash'] The blockchain hash field
+ * @param {string} [options.PREVIOUS_HASH_FIELD='prev'] The blockchain previous hash field
+ * @param {string} [options.NONCE_FIELD='nonce'] The blockchain hash field
  * @param {string} [options.EVENTS_COLLECTION_NAME=`${collectionName}_events`]
@@ -42,2 +56,9 @@ *  The events collection name
  *  of a entity-local one
+ * @param {number} [options.BLOCKCHAIN_HASH_DIFFICULTY=0]
+ *  Blockchain hash generation difficulty
+ * @param {boolean} [options.WITH_BLOCKCHAIN_HASH=false]
+ *  Does the model have a blockchain hash generated version
+ *  after version
+ * @param {boolean} [options.BLOCKCHAIN_HASH_GENESIS=0000000000000000000000000000000000000000000000000000000000000000]
+ *  Genesis hash value
  *
@@ -57,5 +78,13 @@ *  The snapshots collection name
           CORRELATION_FIELD: 'correlation_id',
+          CURRENT_HASH_FIELD: 'hash',
+          PREVIOUS_HASH_FIELD: 'prev',
+          NONCE_FIELD: 'nonce',
+          CREATED_AT_FIELD: 'created_at',
           EVENTS_COLLECTION_NAME: `${collectionName}_events`,
           SNAPSHOTS_COLLECTION_NAME: `${collectionName}_snapshots`,
           WITH_GLOBAL_VERSION: false,
+          WITH_BLOCKCHAIN_HASH: false,
+          BLOCKCHAIN_HASH_DIFFICULTY: 0,
+          BLOCKCHAIN_HASH_GENESIS:
+            '0000000000000000000000000000000000000000000000000000000000000000',
         },
@@ -185,2 +214,74 @@ options,
     /**
+     * Compute the hash for the blockchain mode
+     * @param {number} version
+     * @param {Date} createdAt
+     * @param {object} state
+     * @param {string} [precedingHash=' ']
+     * @param {number} [nonce=0]
+     * @returns {string}
+     */
+    static computeHash(
+      version: number,
+      createdAt: Date | string,
+      state: any,
+      nonce: number,
+      precedingHash: string,
+    ): string {
+      const hash = crypto.createHash('sha256');
+
+      hash.update(
+        `${version}${precedingHash}${createdAt}${JSON.stringify(
+          omit(state, [
+            EventSourced.options.CURRENT_HASH_FIELD,
+            EventSourced.options.PREVIOUS_HASH_FIELD,
+            EventSourced.options.NONCE_FIELD,
+          ]),
+        )}${nonce}`,
+      );
+
+      return hash.digest('hex');
+    }
+
+    /**
+     * Computes a difficult blockchain hash
+     * @param {number} version
+     * @param {Date} createdAt
+     * @param {object} state
+     * @param {string} [precedingHash]
+     * @returns {string}
+     */
+    static computeDifficultHash(
+      version: number,
+      createdAt: Date | string,
+      state: any,
+      precedingHash: string,
+    ): { hash: string; nonce: number } {
+      const difficulty: number =
+        EventSourced.options.BLOCKCHAIN_HASH_DIFFICULTY;
+      let nonce: number = 0;
+      let hash = EventSourced.computeHash(
+        version,
+        createdAt,
+        state,
+        nonce,
+        precedingHash,
+      );
+
+      while (
+        hash.substring(0, difficulty) !== Array(difficulty + 1).join('0')
+      ) {
+        nonce += 1;
+        hash = EventSourced.computeHash(
+          version,
+          createdAt,
+          state,
+          nonce,
+          precedingHash,
+        );
+      }
+
+      return { hash, nonce };
+    }
+
+    /**
      * Reduce events on the given state
@@ -210,2 +311,12 @@ * @param {object[]} events Array of events
 
+        const precedingHash =
+          (options.WITH_GLOBAL_VERSION === true && globalVersion > stateVersion
+            ? lastEvent?.[EventSourced.options.CURRENT_HASH_FIELD]
+            : updated?.[EventSourced.options.CURRENT_HASH_FIELD]) ||
+          EventSourced.options.BLOCKCHAIN_HASH_GENESIS;
+
+        // Apply a timestamp to the event:
+        event[EventSourced.options.CREATED_AT_FIELD] =
+          event[EventSourced.options.CREATED_AT_FIELD] || date.getNow();
+
         updated = reducer(updated, event);
@@ -226,2 +337,20 @@
 
+        // Blockchain logic
+        if (options.WITH_BLOCKCHAIN_HASH === true) {
+          const { hash, nonce } = EventSourced.computeDifficultHash(
+            event.version,
+            event.created_at,
+            event,
+            precedingHash,
+          );
+          updated[EventSourced.options.CURRENT_HASH_FIELD] = hash;
+          updated[EventSourced.options.NONCE_FIELD] = nonce;
+
+          event[EventSourced.options.PREVIOUS_HASH_FIELD] = precedingHash;
+          event[EventSourced.options.CURRENT_HASH_FIELD] =
+            updated[EventSourced.options.CURRENT_HASH_FIELD];
+          event[EventSourced.options.NONCE_FIELD] =
+            updated[EventSourced.options.NONCE_FIELD];
+        }
+
         return deepFreeze(updated);
@@ -228,0 +357,0 @@ }, deepFreeze(cloneDeep(state)));

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Improved metrics

Total package byte prevSize

96857

increased by13.83%

Lines of code

1954

increased by12.88%

No dependency changes