Topology sorting functionality added with docs

docs/source/quickstart.rst

@@ -6,4 +6,4 @@ Installation with package manager npm:
 
 .. code-block:: bash
 
-    $ npm install bigchaindb-driver
+    $ npm install bigchaindb-driver --save

docs/source/usage.rst

@@ -35,12 +35,14 @@ A simple connection with BigchainDB can be established like this.
 
 	const conn = new driver.Connection(API_PATH)
 
-It is also possible to connect to a BigchainDB node of the IPDB test net.
-To do so, you need to pass the **app_id and app_key**.
+Previously you could connect to IPDB testnet, but it has been shutdown.
+Today, you can create an account for the 'BigchainDB Testnet' here_.
+.. _here: https://testnet.bigchaindb.com/?utm_source=3Scale&utm_campaign=21a328d6cd-EMAIL_CAMPAIGN_2018_01_18&utm_medium=email&utm_term=0_b98508b5a9-21a328d6cd-67355241
+To use the tesnet, you need to pass the **app_id and app_key** to get access.
 
 .. code-block:: js
 
-	let bdb = new driver.Connection('https://test.ipdb.io/api/v1/', {
+	let bdb = new driver.Connection('https://test.bigchaindb.com/api/v1/', {
 		app_id: 'dgi829l9',
 		app_key: 'u008ik1bf83b43ce3a95uu0727e66fb9'
 	})
@@ -291,7 +293,7 @@ Let’s perform a text search for all metadata that contains the word '1.32':
 .. code-block:: js
 
 	conn.searchMetadata('1.32')
-    		.then(assets => console.log('Found assets with serial number Bicycle Inc.:', assets))
+    		.then(assets => console.log('Found assets with with metadata equal to "1.32"', assets))
 
 Which leads to following result:
 
@@ -779,6 +781,20 @@ Here is a better overview of the flow of the tokens.
 | ``Carly`` |   1        | ``TRANSFER 2``  |
 +-----------+------------+-----------------+
 
+Topology Sorting
+----------------
+It is possible to retrieve all transactions for a specific `asset_id` with the API Endpoint_ `/transactions?asset_id`
+.. _Endpoint: https://docs.bigchaindb.com/projects/server/en/latest/http-client-server-api.html#get--api-v1-transactions?asset_id=asset_id&operation=CREATE|TRANSFER
+But, there is no guarantee that the transactions are listed in the correct order. We've provided a util method which helps you sorting these transactions in the correct order. The method uses inputs and outputs to build a so-called graph of transactions and returns an object with all ordered transactions.
+In code, it looks like this:
+
+.. code-block:: js
+
+	conn.listTransactions(tx.id, 'TRANSFER'))
+    .then(txArray => driver.Transaction.topsortTransactions(txArray))
+    .then(sortedTxs => console.log(sortedTxs))
+
+
 
 .. TODO:
 .. - Add lexer: https://stackoverflow.com/questions/4259105/which-sphinx-code-block-language-to-use-for-json

package.json

@@ -65,16 +65,17 @@
     "buffer": "^5.0.2",
     "clone": "^2.1.0",
     "core-js": "^2.4.1",
+    "crypto-conditions": "^2.0.1",
     "decamelize": "^2.0.0",
     "es6-promise": "^4.0.5",
     "fetch-ponyfill": "^4.0.0",
-    "crypto-conditions": "^2.0.1",
     "isomorphic-fetch": "^2.2.1",
     "js-sha3": "^0.7.0",
     "js-utility-belt": "^1.5.0",
     "json-stable-stringify": "^1.0.1",
     "query-string": "^5.0.0",
     "sprintf-js": "^1.0.3",
+    "toposort": "^1.0.6",
     "tweetnacl": "^1.0.0"
   },
   "keywords": [

src/index.js

@@ -4,3 +4,4 @@ export Connection from './connection'
 export Transaction from './transaction'
 export ccJsonLoad from './utils/ccJsonLoad'
 export ccJsonify from './utils/ccJsonify'
+export topsortTransactions from './utils/topologySorting'

src/utils/topologySorting.js

@@ -0,0 +1,27 @@
+import toposort from 'toposort'
+
+function generateGraph(txs) {
+    const graph = []
+    txs.forEach(tx => {
+        tx.inputs.forEach(input => {
+            if (input.fulfills) {
+                graph.push([tx.id, input.fulfills.transaction_id])
+            }
+        })
+    })
+
+    return graph
+}
+
+
+/**
+ * @public
+ * Topological sort algorithm for transactions
+ * Used for endpoint: /transactions?assetId
+ * @param {object} txs Array of transactions
+ * @returns {object} Returns transactions in order of dependency
+ */
+export default function topsortTransactions(txs) {
+    const graph = generateGraph(txs)
+    return toposort(graph).reverse()
+}