check-ethereum-scanner
Version:
Safety checks for new Ethereum tokens
85 lines (72 loc) • 2.6 kB
JavaScript
/*
ISC License
Copyright (c) 2019, Pierre-Louis Despaigne
Permission to use, copy, modify, and/or distribute this software for any
purpose with or without fee is hereby granted, provided that the above
copyright notice and this permission notice appear in all copies.
THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
*/
const multiC = require('multicodec');
const { hexStringToBuffer, profiles } = require('./profiles');
const { cidV0ToV1Base32 } = require('./helpers');
module.exports = {
//export some helpers functions
helpers: {
cidV0ToV1Base32,
},
/**
* Decode a Content Hash.
* @param {string} hash an hex string containing a content hash
* @return {string} the decoded content
*/
decode: function (contentHash) {
const buffer = hexStringToBuffer(contentHash);
const codec = multiC.getCodec(buffer);
const value = multiC.rmPrefix(buffer);
let profile = profiles[codec];
if (!profile) profile = profiles['default'];
return profile.decode(value);
},
/**
* Encode an IPFS address into a content hash
* @param {string} ipfsHash string containing an IPFS address
* @return {string} the resulting content hash
*/
fromIpfs: function (ipfsHash) {
return this.encode('ipfs-ns', ipfsHash);
},
/**
* Encode a Swarm address into a content hash
* @param {string} swarmHash string containing a Swarm address
* @return {string} the resulting content hash
*/
fromSwarm: function (swarmHash) {
return this.encode('swarm-ns', swarmHash);
},
/**
* General purpose encoding function
* @param {string} codec
* @param {string} value
*/
encode: function (codec, value) {
let profile = profiles[codec];
if (!profile) profile = profiles['default'];
const encodedValue = profile.encode(value);
return multiC.addPrefix(codec, encodedValue).toString('hex');
},
/**
* Extract the codec of a content hash
* @param {string} hash hex string containing a content hash
* @return {string} the extracted codec
*/
getCodec: function (hash) {
let buffer = hexStringToBuffer(hash);
return multiC.getCodec(buffer);
},
}