Merge pull request #108 from michielmulders/doc-seed-func

Doc seed functionality added

docs/source/advanced.rst

@@ -0,0 +1,81 @@
+=================
+Advanced Examples
+=================
+
+Crypto Conditions
+-----------------
+
+Let's start with a basic use case example. Alice bought a bicycle for €240.
+She will use the bike for a year and will give it to her daughter afterwards.
+First, we create an asset registering the bicycle:
+
+.. code-block:: js
+
+    const txCreateAliceSimple = driver.Transaction.makeCreateTransaction(
+        {'asset': 'bicycle'},
+        {'purchase_price': '€240'},
+        [ 
+            driver.Transaction.makeOutput(driver.Transaction.makeEd25519Condition(alice.publicKey))
+        ],
+        alice.publicKey
+    )
+
+    const txCreateAliceSimpleSigned = driver.Transaction.signTransaction(txCreateAliceSimple, alice.privateKey)
+
+After a year, she decides it's time to transfer the bicycle to her daughter Carly.
+However, Alice wants to maintain the right over the bike so she can possibly sell it. If she would transfer the bicycle to Carly, she won't be able to do this.
+So, Alice needs a crypto conditions that defines that she or her daughter can sign the ``TRANSFER`` transaction to a possible buyer.
+
+We need to define a threshold as well. This defines how many persons have to sign the transaction to ``TRANSFER`` it.
+In this case, we define two subconditions with the public keys from Alice and Carly. Next, we set the threshold to **one**.
+This means that just one of the subconditions has to sign the transaction to transfer it.
+This can be the mother Alice, or Carly herself. 
+
+.. code-block:: js
+    
+    // Create condition for Alice and Carly
+    let subConditionFrom = driver.Transaction.makeEd25519Condition(alice.publicKey, false)
+    let subConditionTo = driver.Transaction.makeEd25519Condition(carly.publicKey, false)
+
+    // Create condition object with threshold and subconditions
+    let condition = driver.Transaction.makeThresholdCondition(1, [subConditionFrom, subConditionTo])
+
+    // Generate output with condition added
+    let output = driver.Transaction.makeOutput(condition)
+
+    // Add Carly to the output.public_keys field so she is the owner
+    output.public_keys = [carly.publicKey]
+
+    let transaction = driver.Transaction.makeTransferTransaction(
+        txCreateAliceSimpleSigned,
+        {'meta': 'Transfer to new user with conditions'},
+        [output],
+        0
+    );
+
+    // Add alice as previous owner
+    transaction.inputs[0].owners_before = [alice.publicKey]
+
+    // Because the addition of crypto conditions, the id for the transaction has to be regenerated
+    delete transaction.id
+    transaction.id = sha3.sha3_256
+        .create()
+        .update(driver.Transaction.serializeTransactionIntoCanonicalString(transaction))
+        .hex()
+
+    // Alice has to sign this transfer because she is still the owner of the created asset
+    let signedCryptoConditionTx = driver.Transaction.signTransaction(transaction, alice.privateKey)
+
+As you can see, we need to generate a new transactionId because we have added crypto conditions.
+We do this with the js-sha3 package, you need to install this package through ``npm``:
+
+``npm install --save js-sha3``
+
+Don't forget to import the package in your code:
+
+.. code-block:: js
+
+    import * as sha3 from 'js-sha3'
+
+
+.. TODO: Document Utils when finished

docs/source/conf.py

@@ -105,7 +105,8 @@ html_theme = 'sphinx_rtd_theme'
 # Add any paths that contain custom static files (such as style sheets) here,
 # relative to this directory. They are copied after the builtin static files,
 # so a file named "default.css" will overwrite the builtin "default.css".
-html_static_path = ['nstatic']
+# html_static_path = ['nstatic']
+# Commented out this option because Sphinx can not find the path
 
 # Custom sidebar templates, must be a dictionary that maps document names
 # to template names.

docs/source/index.rst

@@ -8,6 +8,7 @@ BigchainDB Javascript Driver Documentation
 	readme
 	quickstart
 	usage
+	advanced
 
 Indices and tables
 ==================

docs/source/usage.rst

@@ -358,6 +358,32 @@ Recap: Asset Creation & Transfer
 		.then(assets => console.log('Found assets with serial number Bicycle Inc.:', assets))
     
 
+Ed25519Keypair Seed Functionality 
+---------------------------------
+
+BigchainDB JavaScript driver allows you to create a keypair based on a seed. 
+The constructor accepts a 32 byte seed. One of the ways to create a seed from 
+a string (e.g. a passphrase) is the one used by ``bip39``, specifically the function ``mnemonicToSeed``.
+
+Install bip39 with npm: ``npm install bip39``
+
+Next, require ``bip39`` in your file like this: ``var bip39 = require('bip39')``
+
+At last, we can create the keypair based on a string. The function will transform the string to a byte array.
+As our constructor ``Ed25519Keypair()`` only accepts a seed of 32 bytes, we slice the first 32 bytes: ``slice(0,32)``.
+
+.. code-block:: js
+
+	var keypair = new driver.Ed25519Keypair(bip39.mnemonicToSeed("yourString").slice(0, 32))
+
+You can use the ``Ed25519Keypair()`` constructor as well without seed.
+
+.. code-block:: js
+
+	var keypair = new driver.Ed25519Keypair()
+
+
+
 Websocket Event Stream API Usage
 --------------------------------
 
@@ -614,7 +640,6 @@ Output of above code looks like this. As you can see, Chris has no spent output,
 	Spent outputs for Chris:  0
 	Unspent outputs for Chris:  1
 
-
 Divisible Assets
 ----------------