setProvider
=====================

.. code-block:: javascript

    web3.setProvider(myProvider)
    web3.eth.setProvider(myProvider)
    web3.shh.setProvider(myProvider)
    web3.bzz.setProvider(myProvider)
    ...

Will change the provider for its module.

.. note:: When called on the umbrella package ``web3`` it will also set the provider for all sub modules ``web3.eth``, ``web3.shh``, etc EXCEPT ``web3.bzz`` which needs a separate provider at all times.

----------
Parameters
----------

1. ``Object`` - ``myProvider``: :ref:`a valid provider <web3-providers>`.

-------
Returns
-------

``Boolean``

-------
Example
-------

.. code-block:: javascript

    var Web3 = require('web3');
    var web3 = new Web3(new Web3.providers.HttpProvider('http://localhost:8545'));

    // change provider
    web3.setProvider(new Web3.providers.WebsocketProvider('ws://localhost:8546'));


------------------------------------------------------------------------------

providers
=====================

.. code-block:: javascript

    web3.providers
    web3.eth.providers
    web3.shh.providers
    web3.bzz.providers
    ...

Contains the current available :ref:`providers <web3-providers>`.

----------
Value
----------

``Object`` with the following providers:

    - ``Object`` - ``HttpProvider``: The HTTP provider is **deprecated**, as it won't work for subscriptions.
    - ``Object`` - ``WebsocketProvider``: The Websocket provider is the standard for usage in legacy browsers.
    - ``Object`` - ``IpcProvider``: The IPC provider is used node.js dapps when running a local node. Gives the most secure connection.
    - ``Object`` - ``givenProvider``: When using web3.js in an Enthereum compatible browser, this will be set with the current native provider by that browser. Doesn't need to be instantiated.

-------
Example
-------

.. code-block:: javascript

    var Web3 = require('web3');
    // use the given Provider, e.g in Mist, or instantiate a new websocket provider
    var web3 = new Web3(Web3.providers.givenProvider || new Web3.providers.WebsocketProvider('ws://localhost:8546'));


------------------------------------------------------------------------------


currentProvider
=====================

.. code-block:: javascript

    web3.currentProvider
    web3.eth.currentProvider
    web3.shh.currentProvider
    web3.bzz.currentProvider
    ...

Will return the current provider, otherwise ``null``.


-------
Returns
-------

``Object``: The current provider set or ``null``;

-------
Example
-------

.. code-block:: javascript
    if(!web3.currentProvider)
        web3.setProvider(new web3.providers.HttpProvider("http://localhost:8545"));

------------------------------------------------------------------------------

BatchRequest
=====================

.. code-block:: javascript

    new web3.BatchRequest()
    new web3.eth.BatchRequest()
    new web3.shh.BatchRequest()
    new web3.bzz.BatchRequest()

Class to create and execute batch requests.

----------
Parameters
----------

none

-------
Returns
-------

``Object``: With the following methods:

    - ``add(request)``: To add a request object to the batch call.
    - ``execute()``: Will execute the batch request.

-------
Example
-------

.. code-block:: javascript

    var contract = new web3.eth.Contract(abi, address);

    var batch = new web3.BatchRequest();
    batch.add(web3.eth.getBalance.request('0x0000000000000000000000000000000000000000', 'latest', callback));
    batch.add(contract.methods.balance(address).call.request({from: '0x0000000000000000000000000000000000000000'}, callback2));
    batch.execute();


------------------------------------------------------------------------------

extend
=====================

.. code-block:: javascript

    web3.extend(methods)
    web3.eth.extend(methods)
    web3.shh.extend(methods)
    web3.bzz.extend(methods)
    ...

Allows extending the web3 modules.

.. note:: You also have ``*.extend.formatters`` as additional formatter functions to be used for in and output formatting. Please see the `source file <https://github.com/ethereum/web3.js/blob/master/packages/web3-core-helpers/src/formatters.js>`_ for function details.

----------
Parameters
----------

1. ``methods`` - ``Object``: Extension object with array of methods description objects as follows:
    - ``property`` - ``String``: (optional) The name of the property to add to the module. If no property is set it will be added to the module directly.
    - ``methods`` - ``Array``: The array of method descriptions:
        - ``name`` - ``String``: Name of the method to add.
        - ``call`` - ``String``: The RPC method name.
        - ``params`` - ``Number``: (optional) The number of parameters for that function. Default 0.
        - ``inputFormatter`` - ``Array``: (optional) Array of inputformatter functions. Each array item responds to a function parameter, so if you want some parameters not to be formatted, add a ``null`` instead.
        - ``outputFormatter - ``Function``: (optional) Can be used to format the output of the method.


----------
Returns
----------

``Object``: The extended module.

-------
Example
-------

.. code-block:: javascript

    web3.extend({
        property: 'myModule',
        methods: [{
            name: 'getBalance',
            call: 'eth_getBalance',
            params: 2,
            inputFormatter: [web3.extend.formatters.inputAddressFormatter, web3.extend.formatters.inputDefaultBlockNumberFormatter],
            outputFormatter: web3.utils.hexToNumberString
        },{
            name: 'getGasPriceSuperFunction',
            call: 'eth_gasPriceSuper',
            params: 2,
            inputFormatter: [null, web3.utils.numberToHex]
        }]
    });

    web3.extend({
        methods: [{
            name: 'directCall',
            call: 'eth_callForFun',
        }]
    });

    console.log(web3);
    > Web3 {
        myModule: {
            getBalance: function(){},
            getGasPriceSuperFunction: function(){}
        },
        directCall: function(){},
        eth: Eth {...},
        bzz: Bzz {...},
        ...
    }


------------------------------------------------------------------------------