Ethereum Sign up or log in to customize your list._ Here's how it works: Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top up vote 4 down vote favorite 1 I am studying about dApps and Ethereum.I did get the Solidity part but I am confused about the front-end apps.Is it possible that I use web framework like PHP Laravel/Rails for Frontend/Db operations and interact with backend Bloackchain via web3js or anything?web3js dapps up vote 4 down vote Yes.There are two approaches to consider You can interact with Web3 on the client side and JavaScript The user uses Mist or Parity browser or MetaMask and are connected to their own Ethereum node All interaction with the user wallet (private keys) happens on the client side, in JavaScript This is safe because the user does not need to give the control of his or her private keys to the service provider You can still render pages in whatever backend programming language you wish, but currently web browsers do not support other scripting languages besides JavaScript Here is a tutorial to build a frontend.

Old fashioned way You can interact with Ethereum node on the server-side as you would interact on the client side Web3 has standardish implementation for all programming languages (except maybe not PHP).Web3.py allows interaction from Python, you can use Web3.js in Node.These libraries speak to Ethereum node running locally on the server side over JSON-RPC You might need to do accounting for your users, a non-trivial task that I would not recommend non-experienced programmer to try Also see Executing a Smart Contract in a Mobile App up vote 0 down vote I suggest you to start with this kind of boilerplate.They let's you to start with latest technologies.Browse other questions tagged web3js dapps or ask your own question.The Mist browser is the tool of choice to browse and use Ðapps.For the Mist API see the MISTAPI.md.Please check the Mist troubleshooting guide for help.If you want to install the app from a pre-built version on the release page, you can simply run the executeable after download.

For updating simply download the new version and copy it over the old one (keep a backup of the old one if you want to be sure).The data folder for Mist is stored in other places: For development, a Meteor server will need to be started to assist with live reload and CSS injection.Once a Mist version is released the Meteor frontend part is bundled using the meteor-build-client npm package to create pure static files.To run mist in development you need: Install the latter ones via: Now you're ready to initialise Mist for development: To update Mist in the future, run: For development we start the interface with a Meteor server for autoreload etc. Start the interface in a separate terminal window: In the original window you can then start Mist with: NOTE: client-binaries (e.g.geth) specified in clientBinaries.json will be checked during every startup and downloaded if out-of-date, binaries are stored in the config folder NOTE: use --help to display available options, e.g.

--loglevel debug (or trace) for verbose output Start the wallet app for development, in a separate terminal window: In the original window you can then start Mist using wallet mode: This is useful if you have a node running on another machine, though note that it's less secure than using the default IPC method.bitcoin hashrate poolsYou can pass command-line options directly to Geth by prefixing them with --node- in the command-line invocation: The --rpc Mist option is a special case.bitcoin ware kaufenIf you set this to an IPC socket file path then the --ipcpath option automatically gets set, i.e.: ...is the same as doing... See this guide to quickly set up a local private network on your computer: /evertonfraga/9d65a9f3ea399ac138b3e40641accf23 To run a private network you will need to set the IPC path, network id and data folder: NOTE: since ipcpath is also a Mist option you do not need to also include a --node-ipcpath option.bitcoin elliott wave

You can also launch geth separately with the same options prior starting Mist.Our build system relies on gulp and electron-builder.meteor-build-client bundles the meteor-based interface.Install it via: Furthermore cross-platform builds require additional electron-builder dependencies.apt-get litecoin-qtOn macOS those are: To generate the binaries for Mist run: /ethereum/meteor-dapp-wallet): The generated binaries will be under dist_mist/release or dist_wallet/release.apt-get litecoin-qtTo build binaries for specific platforms (default: all available) use the following flags: With the walletSource you can specify the Wallet branch to use, default is master: Note: applicable only when combined with --wallet Spits out the MD5 checksums of distributables.bitcoin chuck norris

It expects installer/zip files to be in the generated folders e.g.dist_mist/release First make sure to build Mist with: Note: Integration tests are not yet supported on Windows.Events and logs are important in Ethereum because they facilitate communication between smart contracts and their user interfaces.bitcoin geforce miningIn traditional web development, a server response is provided in a callback to the frontend.ethereum miner debianIn Ethereum, when a transaction is mined, smart contracts can emit events and write logs to the blockchain that the frontend can then process.bitcoin aud graphThere are different ways to address events and logs.This technical introduction will explain some sources of confusion regarding events and some sample code for working with them.Events can be confusing because they can be used in different ways.

An event for one may not look like an event for another.There are 3 main use cases for events and logs:The terminology between events and logs is another source of confusion and this will be explained in the third use case.The simplest use of an event is to pass along return values from contracts, to an app’s frontend.To illustrate, here is the problem.Assuming exampleContract is an instance of ExampleContract, a frontend using web3.js, can obtain a return value by simulating the contract execution:However, when web3.js submits the contract call as a transaction, it cannot obtain the return value[1]:The return value of a sendTransaction method is always the hash of the transaction that’s created.Transactions don’t return a contract value to the frontend because transactions are not immediately mined and included in the blockchain.The recommended solution is to use an event, and this is one of the intended purposes for events.The third use case is quite different from what’s been covered, and that is using events as a significantly cheaper form of storage.

In the Ethereum Virtual Machine (EVM) and Ethereum Yellow Paper[2], events are referred to as logs (there are LOG opcodes).When speaking of storage, it would be technically more accurate to say that data can be stored in logs, as opposed to data being stored in events.However, when we go a level above the protocol, it is more accurate to say that contracts emit or trigger events which the frontend can react to.Whenever an event is emitted, the corresponding logs are written to the blockchain.The terminology between events and logs is another source of confusion, because the context dictates which term is more accurate.Logs were designed to be a form of storage that costs significantly less gas than contract storage.Logs basically[3] cost 8 gas per byte, whereas contract storage costs 20,000 gas per 32 bytes.Although logs offer gargantuan gas savings, logs are not accessible from any contracts[4].Three use cases have been presented for events.First, using an event to simply get a return value from a contract function invoked with sendTransaction().