א：媒体链宇宙操纵引擎___下载.zip

# א [](https://badge.fury.io/js/aleph) [](https://travis-ci.org/mediachain/aleph.svg?branch=master) [](https://github.com/feross/standard) [](https://coveralls.io/github/mediachain/aleph?branch=master) *The Aleph's diameter was probably little more than an inch, but all space was there, actual and undiminished. Each thing (a mirror's face, let us say) was infinite things, since I distinctly saw it from every angle of the universe[¹]* Aleph is part of the [mediachain](http://mediachain.io) project and is an integral component of the [Phase II architecture](https://blog.mediachain.io/looking-backwards-looking-forwards-9149bf00f876#.kkym75h9h). Aleph provides two main components. First is a client for the HTTP API exposed by [concat][concat], the reference go peer implementation. Second is a lightweight peer in its own right. For system-wide Mediachain documentation see https://mediachain.github.io/mediachain-docs. ## Installation Aleph requires node 6 or greater, and has primarily been tested with 6.5 and above. To globally install a release from npm: `npm install --global aleph`. This will install the `aleph` command, which provides a remote query command and an interactive REPL for exploring the mediachain network. It also installs the `mcclient` command, which you can use to control and interact with a [concat][concat] node. If you'd prefer to install from the source repository, clone this repo and run `npm install`, followed by `npm link`, which will create a `mcclient` and `aleph` symlinks that run the latest compiled version of the code. This is very useful during development. If you don't want `mcclient` or `aleph` on your path at all, you can just run `npm install` and execute `./bin/mcclient.js` and `./bin/aleph.js` directly instead. ## Usage Installing the `aleph` package will install two command line tools: `mcclient` and `aleph`. ### `mcclient` `mcclient` is a wrapper around the HTTP API exposed by [concat][concat], aleph's heavy-lifting counterpart. `mcclient` contains several sub-commands, so the general invocation is `mcclient [global-options] <command> [command-options]`. At the moment, the only global option is `--apiUrl` or `-p`, which sets the location of the remote node's HTTP API. By default, `mcclient` will attempt to connect to a concat node running on localhost at port 9002, which is concat's default listen address for the HTTP API. If you've configured concat to run on a different port or on a remote machine, use the `-p` flag to pass in a new URL, e.g. `mcclient -p http://localhost:5678 id` Some useful commands include: - `id`: print the node's peer id and publisher id - `status`: - with no arguments, prints the current status (`online`, `offline`, or `public`) - set the status with e.g. `mcclient status online` - `publish`: publish JSON metadata to the node's local store. see `mcclient publish --help` for more info. - `statement`: retrieve a statement by its id - `query`: run a mediachain query against the node's local store. To see a full list of supported commands, run `mcclient --help` ### `aleph` While `mcclient` is a front-end for the golang peer implementation [concat][concat], the `aleph` command provides access to the javascript peer implementation. The two are interoperable, but they do not have feature parity. Most notably, the javascript peer has no local storage for mediachain statements or data objects, so it can't be used to provide mediachain data. However, `aleph` is useful for interacting with local and remote `concat` nodes, and for exploring the mediachain network and peer-to-peer architecture. There are currently two `aleph` subcommands, `aleph repl` and `aleph query` #### `aleph repl` The `aleph repl` command provides an interactive Read-Eval-Print-Loop for controlling a javascript mediachain node. When you start the repl, a new peer identity is created and stored in the `~/.mediachain/aleph` directory. You can override that default with the `--identityPath` flag. The repl provides a javascript prompt, and a global `node` object. This is an instance of the [`MediachainNode` class](https://github.com/mediachain/aleph/src/peer/node.js), which implements the peer-to-peer protocols. The repl can be used to remotely interact with another node using the mediachain protocol. For example: ```javascript א > node.ping('/ip4/54.205.184.122/tcp/9001/p2p/QmeiY2eHMwK92Zt6X4kUUC3MsjMmVb2VnGZ17DhnhRPCEQ') true ``` The long string above is a [multiaddr](https://github.com/multiformats/multiaddr/), which is a format for representing and combining addresses for multiple network protocols. The string above is for the peer-to-peer node with id `QmeiY2eHMwK92Zt6X4kUUC3MsjMmVb2VnGZ17DhnhRPCEQ`, located at the IP4 address `54.205.184.122`, on tcp port `9001`. The `/p2p/` protocol identifier is not yet part of the multiaddr standard, but it is [in the works](https://github.com/multiformats/multiaddr/pull/27) as a replacement for the `/ipfs/` identifier, and we've adopted it in anticipation of it being integrated into the standard soon. Let's make our addresses a bit simpler by connecting to the Mediachain Labs directory server: ```javascript א > node.setDirectory('/ip4/52.7.126.237/tcp/9000/p2p/QmSdJVceFki4rDbcSrW7JTJZgU9so25Ko7oKHE97mGmkU6') ``` Now we can just use the peer identifier portion of the address, and the directory will provide us with the full address behind the scenes: ```javascript א > node.ping('QmeiY2eHMwK92Zt6X4kUUC3MsjMmVb2VnGZ17DhnhRPCEQ') true ``` You can also provide the directory server address at the command line when launching the repl: ```bash $ aleph repl --dir /ip4/52.7.126.237/tcp/9000/p2p/QmSdJVceFki4rDbcSrW7JTJZgU9so25Ko7oKHE97mGmkU6 ``` This will set the directory address on startup, and avoid the need for the `node.setDirectory` call. ##### Pairing a remote node Since the aleph repl is at its most useful when interacting with a remote node, there's built-in support for "pairing" the javascript aleph node to a remote node (most likely a `concat` node). To do so, just provide the `--remotePeer` flag when launching the repl, and give it a multiaddr where the peer is located: ```bash $ aleph repl --remotePeer /ip4/54.205.184.122/tcp/9001/p2p/QmeiY2eHMwK92Zt6X4kUUC3MsjMmVb2VnGZ17DhnhRPCEQ ``` Now, in addition to the global `node` object, you also have a `remote` object that represents the remote peer. ```javascript א > remote.query('SELECT * FROM images.dpla LIMIT 1') [ { value: { simple: [Object] } } ] ``` The query result is printed at the repl in condensed form. To examine it further, we can use the "magic" `_` variable, which holds the result of the last repl command. Assign it to a new variable, and we can interact with it more easily: ```javascript var result = _ console.dir(result[0].value.simple) { stmt: { id: '4XTTM4K8sqTb7xYviJJcRDJ5W6TpQxMoJ7GtBstTALgh5wzGm:1478267497:1', publisher: '4XTTM4K8sqTb7xYviJJcRDJ5W6TpQxMoJ7GtBstTALgh5wzGm', namespace: 'images.dpla', body: { simple: { object: 'QmeFJSTPKSEiNqebxZvYcduWH8UBmxqNq724gHEQnxV5D1', refs: [ 'dpla_1ff6b36174426026847c8f8ca216ffa9' ], tags: [], deps: [ 'QmYGRQYmWC3BAtTAi88mFb7GVeFsUKGM4nm25SBUB9vfc9' ] } }, timestamp: 1478267497, signature: Buffer [...] } } ``` To also fetch the data objects associated with each result, use `remote.queryWithData` instead of `remote.query`. #### `aleph query` `aleph query --remotePeer <peerAddress> <queryString>` will execute a query on a remote peer using the peer-to-peer query protocol. This is very similar to the `mcclient query`