scryinfo/lib/db/scryDBIPFS.js

A real data storage library on ethereum

/**
    en: ScryDBIPFS is a subclass of ScryDBBase, it has achieved 'get' and 'set' functions through IPFS.
    @author Danny Yan
    @date 2017-07
*/
var util = require('util');
var fs = require("fs");
var Status = require("../scryStatus.js");
var ScryDBBase = require("./scryDBBase.js");
var ipfsAPI = require('ipfs-api');
var concat = require("concat-stream");

function ScryDBIPFS() {

}

util.inherits(ScryDBIPFS, ScryDBBase);

ScryDBIPFS.prototype.connect = function(url, callback) {
	this.ipfs = ipfsAPI(url);
	callback(this.ipfs != null);
};

ScryDBIPFS.prototype.get = function(key, callback) {
    this.ipfs.files.get(key.substring(2), function(err, stream) {
        if (err) {
            console.log("接收到ipfs数据错误", err);
            typeof(callback) == "function" && callback(Status.returnError( err.toString(), err));
            return;
        }
        stream.on('data', (file) => {
            file.content.pipe(concat((content) => {
                console.log("接收到ipfs数据成功:", file.path);
                typeof(callback) == "function" && callback(Status.returnOK( content.toString() ));
            }));
        })
    });
};

ScryDBIPFS.prototype.set = function(content, callback) {
	var buffered = Buffer.from(content);
    // 保存到ipfs
    this.ipfs.files.add(buffered, function(err, _files) {
        if (err) {
            typeof(callback) == "function" && callback(Status.returnError(err));
            console.log("ipfs存储失败:", err);
            return;
        }
        console.log("存储到ipfs数据成功:", _files[0].hash);
        typeof(callback) == "function" && callback(Status.returnOK( "SC"+_files[0].hash ));
    });
};

module.exports = ScryDBIPFS;