TransportIPFS.js

/* global Ipfs, IpfsHttpClient*/
/* eslint-disable camelcase, indent, quotes, nonblock-statement-body-position, curly */
/*
This is a shim to the IPFS library, (Lists are handled in YJS or OrbitDB)
See https://github.com/ipfs/js-ipfs but note its often out of date relative to the generic API doc.
*/
/* Note that I'm told (May 2023) that js-ipfs is being deprecated in favor of Helia https://github.com/ipfs/helia
 but as far as I can see Helia is incomplete
 1: Doesnt appeat to have an equivalent of ipfs.catReadableStream() API
 2: Doesnt solve the hanging .get problem https://github.com/ipfs/js-ipfs/issues/1165#issuecomment-1564805572
  which has just been closed with a reference to AbortSignals, which I cannot see working since
  the app layer has no way of knowing how long a .get should take before falling back to HTTP.

  Therefore I'm not planning to do the migration to Helia
  - if anyone wants to please feel free to submit a PR,
  their migration instructions are at https://github.com/ipfs/helia/wiki/%F0%9F%9A%9B-Migrating-from-js-IPFS
  and look fairly simple - except for the apparant absence of getReadableStream()
  (which I would presume will get implemented at some point)
 */

// TODO-IPFS Note API changes in https://github.com/ipfs/js-ipfs/issues/1721 probably all ipfs.files -> ipfs.

// Library packages other than IPFS
const Url = require('url');
const debug = require('debug')('dweb-transports:ipfs');

// Local packages
const httptools = require('./httptools'); // Expose some of the httptools so that IPFS can use it as a backup

// IPFS components
let IPFS; // TODO-SPLIT move this line lower when fix structure
// TODO-SPLIT remove this import depend on archive.html or node to pre-load
// IPFS = require('ipfs');
// TODO-SPLIT remove this import depend on archive.html or node to pre-load
// const ipfsAPI = require('ipfs-http-client');
// We now get this from IPFS.CID
// const CID = require('cids');


// Other Dweb modules
const { CodingError, TransportError } = require('./Errors'); // Standard Dweb Errors
const Transport = require('./Transport.js'); // Base class for TransportXyz
const Transports = require('./Transports'); // Manage all Transports that are loaded
const utils = require('./utils'); // Utility functions

const defaultoptions = {
    repo: '/tmp/dweb_ipfsv3107', // TODO-IPFS restarted 2018-10-06 because was caching connection ws-star
    // init: false,
    // start: false,
    // TODO-IPFS-Q how is this decentralized - can it run offline? Does it depend on star-signal.cloud.ipfs.team
    config: {
        //      Addresses: { Swarm: [ '/dns4/star-signal.cloud.ipfs.team/wss/p2p-webrtc-star']},  // For Y - same as defaults
        //      Addresses: { Swarm: [ ] },   // Disable WebRTC to test browser crash, note disables Y so doesnt work.
        // Addresses: {Swarm: ['/dns4/ws-star.discovery.libp2p.io/tcp/443/wss/p2p-websocket-star']}, // from https://github.com/ipfs/js-ipfs#faq 2017-12-05 as alternative to webrtc works sort-of
        // Bootstrap: ['/dns4/dweb.me/tcp/4245/wss/ipfs/QmPNgKEjC7wkpu3aHUzKKhZmbEfiGzL5TP1L8zZoHJyXZW'], // Connect via WSS to IPFS instance at IA on FnF
        Bootstrap: ['/dns4/dweb.me/tcp/4245/wss/ipfs/QmQz3p44VVQDeAieaW28DMjcTVzLbpxqaQB9bkXnyd7HY5'], // Connect via WSS to IPFS instance in Kube at IA
        // Previously was: QmQ921MRjsbP12fHSEDcdFeuHFg6qKDFurm2rXgA5K3RQD on kube
    },
    // init: true, // Comment out for Y
    EXPERIMENTAL: { pubsub: true },
    preload: { enabled: false },
    // Off by default, it never seems to have the content (routing issues) pass as an argument if want to use
    // httpIPFSgateway: "https://ipfs.io",
};

class TransportIPFS extends Transport {
    /*
    IPFS specific transport

    Fields:
    ipfs: object returned when starting IPFS
     */

    constructor(options) {
        super(options);
        ["urlUrlstore", "httpIPFSgateway"].forEach(k => {
            this[k] = options[k];
            delete options[k];
        });
        this.ipfs = undefined;          // Undefined till start IPFS
        this.options = options;         // Dictionary of options
        this.name = "IPFS";             // For console log etc
        this.supportURLs = ['ipfs'];
        this.supportFunctions = ['fetch', 'store', 'seed', 'createReadStream'];   // Does not support reverse
        this.supportFeatures = ['noCache']; // Note doesnt actually support noCache, but immutable is same
        this.setStatus(Transport.STATUS_LOADED);
    }

    _ipfsversion(ipfs, s, cb) {
        ipfs.version((err, data) => {
            if (err) {
                debug("IPFS via %s present but unresponsive: %o", s, data);
                this.ipfstype = "FAILED";
                cb(err);
            } else {
                debug("IPFS available via %s: %o", s, data);
                this.ipfstype = s;
                cb(null, ipfs);
            }
        });
    }

  /**
   * Attempt to connect to IPFS via a local API
   * Note that this ipfs http API has been subject to frequent bit-rot, so encapsulating with error catch
   * @param cb
   * @constructor
   */
    IPFSAPIConnect(cb) {
      cb(new Error("Bit rot in IPFS HTTP API - uncaught promise exception - so skipping"));
      return;
    /*
    const ipfsAPI = global.IpfsHttpClient || window.IpfsHttpClient;
    const ipfs0 = ipfsAPI('http://localhost:5001'); // leaving out the arguments will default to these values
      try {
        ipfs0.version((err, unusedData) => {
          if (err) {
            cb(err)
          } else {
            cb(ipfs0);
          }
        });
      } catch(err) {
        cb(err);
      }

     */
    }

    IPFSAutoConnect(cb) {
      IPFS = global.Ipfs || window.Ipfs;  // Loaded by <script etc but still need a create
      // TODO-SPLIT I think next few lines are wrong, dont think I've seen global.ipfs or window.ipfs but
      // TODO-SPLIT https://github.com/ipfs/js-ipfs implies global.Ipfs but needs a "create" or "new"
      if (global.ipfs) {
          this._ipfsversion(global.ipfs, "global.ipfs", cb );
      } else if (typeof window !== "undefined" && window.ipfs) {
          this._ipfsversion(window.ipfs, "window.ipfs", cb);
      } else {
        try { // Wrap IPFS API - notorious for bit-rot (Changing API's causing crashes)
          // noinspection ES6ConvertVarToLetConst
          // eslint-disable-next-line vars-on-top, no-var
          var ipfs;
          this.IPFSAPIConnect((err, ipfs0) => {
            if (err) {
              debug("IPFS via API failed %s, trying running own IPFS client", err.message);
              ipfs = new IPFS(this.options);
              ipfs.on('ready', () => {
                this._ipfsversion(ipfs, "client", cb);
              });   // This only works in the client version, not on API
              ipfs.on('error', (err1) => {
                debug("IPFS via client error %s", err1.message); // Calls error, note this could be a problem if it gets errors after "ready"
                cb(err1);
              }); // This only works in the client version, not on API
            } else {
              ipfs = ipfs0;
              this._ipfsversion(ipfs, "API", cb); // Note wastes an extra ipfs.version call but that's cheap
            }
          });
        } catch (err) {
          debug("IPFSAutoConnect failed with exception %o", err);
          cb(err, null);
        }
      }
    }

    static setup0(options) {
        /*
            First part of setup, create obj, add to Transports but dont attempt to connect, typically called instead of p_setup if want to parallelize connections.
        */
        const combinedoptions = Transport.mergeoptions(defaultoptions, options.ipfs);
        debug("setup options=%o", combinedoptions);
        const t = new TransportIPFS(combinedoptions);   // Note doesnt start IPFS
        Transports.addtransport(t);
        return t;
    }

    // eslint-disable-next-line consistent-return
    p_setup1(cb) {
      /* Start IPFS connection
          returns     this via cb(err,res) or promise
          errors      This should never "fail" as it will break the Promise.all, it should return "this" but set this.setStatus(Transport.STATUS_FAILED)
       */
      if (cb) { try { f.call(this, cb)} catch(err) { cb(err)}} else { return new Promise((resolve, reject) => { try { f.call(this, (err, res) => { if (err) {reject(err)} else {resolve(res)} })} catch(err) {reject(err)}})} // Promisify pattern v2
      // eslint-disable-next-line no-shadow
      function f(cb) {
        try {
          // Logged by Transports
          this.setStatus(Transport.STATUS_STARTING);   // Should display, but probably not refreshed in most case
          this.IPFSAutoConnect((err, ipfs) => {  // Various errors possible inc websocket
            if (err) {
              debug("Failed to connect %s", err.message);
              this.setStatus(Transport.STATUS_FAILED);
            } else {
              this.ipfs = ipfs;
              this.setStatus(Transport.STATUS_CONNECTED);
            }
            cb(null, this); // Don't fail, report the error and set statust to Transport.STATUS_FAILED
          });
        } catch (err) {
          // Catch errors as IPFS is a notorious bit-rotter (previously working code fails due to changes in its API
          debug("Exception in IPFS.setup1 %o", err);
          this.setStatus(Transport.STATUS_FAILED);
          cb(null, this); // Don't fail, report the error and set statust to Transport.STATUS_FAILED
        }
      }
    }

    p_setup2() {
        if (this.status === Transport.STATUS_FAILED) {
            debug("Stage 1 failed, skipping");
        }
        return this;
    }

    stop(cb) { // TODO-API p_stop > stop
        if (this.ipfstype === "client") {
            this.ipfs.stop((err, res) => {
                this.setStatus(Transport.STATUS_FAILED);
                cb(err, res);
            });
        } else {
            // We didn't start it, don't try and stop it
            this.setStatus(Transport.STATUS_FAILED);
            cb(null, this);
        }
    }
    async p_status() {
        /*
            Return a numeric code for the status of a transport.
            TODO - this no longer works if using the http api
         */
        this.setStatus((await this.ipfs.isOnline()) ? Transport.STATUS_CONNECTED : Transport.STATUS_FAILED);
        return super.p_status();
    }

    // Everything else - unless documented here - should be opaque to the actual structure of a CID
    // or a url. This code may change as its not clear (from IPFS docs) if this is the right mapping.
    static urlFrom(unknown) {
        /*
        Convert a CID into a standardised URL e.g. ipfs:/ipfs/abc123
         */
        if (unknown instanceof IPFS.CID) // TODO-SPLIT - I think there is a way to get this from a types array
            return "ipfs:/ipfs/" + unknown.toBaseEncodedString();
        if (typeof unknown === "object" && unknown.hash) // e.g. from files.add
            return "ipfs:/ipfs/" + unknown.hash;
        if (typeof unknown === "string")    // Not used currently
            return "ipfs:/ipfs/" + unknown;
        throw new CodingError("TransportIPFS.urlFrom: Cant convert to url from", unknown);
    }

    static cidFrom(url) {
        /*
        Convert a URL e.g. ipfs:/ipfs/abc123 into a CID structure suitable for retrieval
        url: String of form "ipfs://ipfs/<hash>" or parsed URL or CID
        returns: CID
        throws:  TransportError if cant convert
         */
        if (url instanceof IPFS.CID) return url;
        if (typeof url === "string") url = Url.parse(url);
        if (url && url.pathname) { // On browser "instanceof Url" isn't valid)
            const patharr = url.pathname.split('/');
            if ((!["ipfs:","dweb:"].includes(url.protocol)) || (patharr[1] !== 'ipfs') || (patharr.length < 3))
                throw new TransportError("TransportIPFS.cidFrom bad format for url should be dweb: or ipfs:/ipfs/...: " + url.href);
            if (patharr.length > 3)
                throw new TransportError("TransportIPFS.cidFrom not supporting paths in url yet, should be dweb: or ipfs:/ipfs/...: " + url.href);
            return new IPFS.CID(patharr[2]);
        } else {
            throw new CodingError("TransportIPFS.cidFrom: Cant convert url", url);
        }
    }

    static _stringFrom(url) {
        // Tool for ipfsFrom and ipfsGatewayFrom
        if (url instanceof IPFS.CID)
            return "/ipfs/"+url.toBaseEncodedString();
        if (typeof url === 'object' && url.path) { // It better be URL which unfortunately is hard to test
            return url.path;
        }
        return undefined;
    }

    static ipfsFrom(url) {
        /*
        Convert to a ipfspath i.e. /ipfs/Qm....
        Required because of strange differences in APIs between files.cat and dag.get  see https://github.com/ipfs/js-ipfs/issues/1229
         */
        url = this._stringFrom(url); // Convert CID or Url to a string hopefully containing /ipfs/
        if (url.indexOf('/ipfs/') > -1) {
            return url.slice(url.indexOf('/ipfs/'));
        }
        throw new CodingError(`TransportIPFS.ipfsFrom: Cant convert url ${url} into a path starting /ipfs/`);
    }

    ipfsGatewayFrom(url) {
        /*
        url: CID, Url, or a string
        returns:    https://ipfs.io/ipfs/<cid>
         */
        url = this._stringFrom(url); // Convert CID or Url to a string hopefully containing /ipfs/
        if (url.indexOf('/ipfs/') > -1) {
            return this.httpIPFSgateway + url.slice(url.indexOf('/ipfs/'));
        }
        throw new CodingError(`TransportIPFS.ipfsGatewayFrom: Cant convert url ${url} into a path starting /ipfs/`);
    }

    static multihashFrom(url) {
        if (url instanceof IPFS.CID)
            return url.toBaseEncodedString();
        if (typeof url === 'object' && url.path)
            url = url.path;     // /ipfs/Q...
        if (typeof url === "string") {
            const idx = url.indexOf("/ipfs/");
            if (idx > -1) {
                return url.slice(idx+6);
            }
        }
        throw new CodingError(`Cant turn ${url} into a multihash`);
    }

    // noinspection JSCheckFunctionSignatures
    async p_rawfetch(url, { timeoutMS = 60000, unusedRelay = false } = {}) {
        /*
        Fetch some bytes based on a url of the form ipfs:/ipfs/Qm..... or ipfs:/ipfs/z....  .
        No assumption is made about the data in terms of size or structure, nor can we know whether it was created with dag.put or ipfs add or http /api/v0/add/

        Where required by the underlying transport it should retrieve a number if its "blocks" and concatenate them.
        Returns a new Promise that resolves currently to a string.
        There may also be need for a streaming version of this call, at this point undefined since we havent (currently) got a use case..

        :param string url: URL of object being retrieved {ipfs|dweb}:/ipfs/<cid> or /
        :resolve buffer: Return the object being fetched. (may in the future return a stream and buffer externally)
        :throws:        TransportError if url invalid - note this happens immediately, not as a catch in the promise
         */
        // Attempt logged by Transports
        if (!url) throw new CodingError("TransportIPFS.p_rawfetch: requires url");
        const cid = TransportIPFS.cidFrom(url);  // Throws TransportError if url bad
        const ipfspath = TransportIPFS.ipfsFrom(url); // Need because dag.get has different requirement than file.cat

        try {
            const res = await utils.p_timeout(this.ipfs.dag.get(cid), timeoutMS, "Timed out IPFS fetch of "+TransportIPFS._stringFrom(cid));   // Will reject and throw TimeoutError if times out
            // noinspection Annotator
            if (res.remainderPath.length)
            { // noinspection ExceptionCaughtLocallyJS
                throw new TransportError("Not yet supporting paths in p_rawfetch");
            }
            let buff;
            if (res.value.constructor.name === "DAGNode") { // Kludge to replace above, as its not matching the type against the "require" above.
                // We retrieved a DAGNode, call files.cat (the node will come from the cache quickly)
                buff = await this.ipfs.cat(ipfspath); // See js-ipfs v0.27 version and  https://github.com/ipfs/js-ipfs/issues/1229 and https://github.com/ipfs/interface-ipfs-core/blob/master/SPEC/FILES.md#cat
            } else { // c: not a file
                debug("Found a raw IPFS block (unusual) - not a DAGNode - handling as such");
                buff = res.value;
            }
            // Success logged by Transports
            return buff;
        } catch (err) { // TimeoutError or could be some other error from IPFS etc
            debug("Caught error '%s' fetching via IPFS", err.message);
            if (!this.httpIPFSgateway) {
                throw (err);
            } else {
                try {
                    debug("Trying IPFS HTTP gateway");
                    let ipfsurl = this.ipfsGatewayFrom(url);
                    return await utils.p_timeout(
                        httptools.p_GET(ipfsurl), // Returns a buffer
                        timeoutMS, "Timed out IPFS fetch of "+ipfsurl)
                } catch (err1) {
                    // Failure logged by Transports:
                    // debug("Failed to retrieve from gateway: %s", err.message);
                    throw err1;
                }
            }
        }
    }

    async p_rawstore(data) {
        /*
        Store a blob of data onto the decentralised transport.
        Returns a promise that resolves to the url of the data

        :param string|Buffer data: Data to store - no assumptions made to size or content
        :resolve string: url of data stored
         */
        console.assert(data, "TransportIPFS.p_rawstore: requires data");
        const buf = (data instanceof Buffer) ? data : new Buffer(data);
        const res = (await this.ipfs.add(buf, { "cid-version": 1, hashAlg: 'sha2-256' }))[0];
        return TransportIPFS.urlFrom(res);
    }

    seed({directoryPath=undefined, fileRelativePath=undefined, ipfsHash=undefined, urlToFile=undefined}, cb) {
        /* Note always passed a cb by Transports.seed - no need to support Promise here
            ipfsHash:       IPFS hash if known (usually not known)
            urlToFile:      Where the IPFS server can get the file - must be live before this called as will fetch and hash
            TODO support directoryPath/fileRelativePath, but to working around IPFS limitation in https://github.com/ipfs/go-ipfs/issues/4224 will need to check relative to IPFS home, and if not symlink it and add symlink
            TODO maybe support adding raw data (using add)

            Note neither js-ipfs-http-client nor js-ipfs appear to support urlstore yet, see https://github.com/ipfs/js-ipfs-http-client/issues/969
        */
        // This is the URL that the IPFS server uses to get the file from the local mirrorHttp
        if (!(this.urlUrlstore && urlToFile)) { // Not doing IPFS
            debug("IPFS.seed support requires urlUrlstore and urlToFile"); // Report, though Transports.seed currently ignores this
            cb(new Error("IPFS.seed support requires urlUrlstore and urlToFile")); // Report, though Transports.seed currently ignores this
        } else {
            // Building by hand becase of lack of support in js-ipfs-http-client
            const url = `${this.urlUrlstore}?arg=${encodeURIComponent(urlToFile)}`;
            // Have to be careful to avoid loops, the call to addIPFS should only be after file is retrieved and cached, and then addIPFS shouldnt be called if already cached
            // noinspection JSIgnoredPromiseFromCall
            httptools.p_GET(url, {retries:0}, (err, res) => {
                if (err) {
                    debug("IPFS.seed for %s failed in http: %s", urlToFile, err.message);
                    cb(err);    // Note error currently ignored in Transports
                } else {
                    debug("Added %s to IPFS key=", urlToFile, res.Key);
                    // Check for mismatch - this isn't an error, for example it could be an updated file, old IPFS hash will now fail, but is out of date and shouldnt be shared
                    if (ipfsHash && ipfsHash !== res.Key) {  debug("ipfs hash doesnt match expected metadata has %s daemon returned %s", ipfsHash, res.Key); }
                    cb(null, res)
                }
            })
        }
    }

  // ==== STREAM SUPPORT ===
  // async p_f_createReadStream(url, {wanturl=false}={}) - Transport superclass ok
  // createReadStreamFunction - Transport superclass ok

  createReadStreamID(url, cb) {
    cb(null, multihashFrom(url));
  }

  // On IPFS catReadableStream returns stream synchronously so flip createReadStreamFetch and createReadStreamSync around from superclass
  createReadStreamSync(multihash, opts, cb) {
    debug("reading from stream %o %o", multihash, opts || "" );
    const start = opts ? opts.start : 0;
    // The videostream library does not always pass an end byte but when
    // it does, it wants bytes between start & end inclusive.
    // catReadableStream returns the bytes exclusive so increment the end
    // byte if it's been requested
    const end = (opts && opts.end) ? start + opts.end + 1 : undefined;
    // This stream will contain the requested bytes
    // For debugging used a known good IPFS video
    // let fakehash="QmedXJYwvNSJFRMVFuJt7BfCMcJwPoqJgqN3U2MYxHET5a"
    // console.log("XXX@IPFS.p_f_createReadStream faking call to",multihash, "with", fakehash)
    // multihash=fakehash;
    const stream = this.ipfs.catReadableStream(multihash, {
      offset: start,
      length: end && end - start
    });
    // Log error messages
    stream.on('error', (err) => debug("IPFS stream error %s", err.message));
    return stream
  }

  createReadStreamFetch(multihash, opts, cb) {
    cb(null, createReadStreamSync(multihash, opts));
  }

  createReadStreamFunction(url, {wanturl=false}={}, cb) {
    /*
    This builds on superclass as has to destroy any previous stream for this file.

    :param string url: URL of object being retrieved of form  magnet:xyzabc/path/to/file  (Where xyzabc is the typical magnet uri contents)
    :param boolean wanturl True if want the URL of the stream (for service workers)
    :resolves to: f({start, end}) => stream (The readable stream.)
    :throws:        TransportError if url invalid - note this happens immediately, not as a catch in the promise
     */
    //Logged by Transports
    //debug("p_f_createreadstream %s", Url.parse(url).href);
    this.createReadStreamID(url, (err, multihash) => {
      if (err) {
        cb(err);
      } else {
        let stream;
        const self = this;
        return function crs(opts) {
          // If we've streamed before, clean up the existing stream
          if (stream && stream.destroy) {
            stream.destroy();
          }
          cb(null, self.createReadStreamSync(multihash, opts));
        };
      }
    });
  }

    static async p_test(opts) {
        console.log("TransportIPFS.test");
        try {
            const transport = await this.p_setup(opts); // Assumes IPFS already setup
            console.log(transport.name,"setup");
            const res = await transport.p_status();
            console.assert(res === Transport.STATUS_CONNECTED);

            let urlqbf;
            const qbf = "The quick brown fox";
            const qbf_url = "ipfs:/ipfs/zdpuAscRnisRkYnEyJAp1LydQ3po25rCEDPPEDMymYRfN1yPK"; // Expected url
            const unusedTesturl = "1114";  // Just a predictable number can work with
            const url = await transport.p_rawstore(qbf);
            console.log("rawstore returned", url);
            const newcid = TransportIPFS.cidFrom(url);  // Its a CID which has a buffer in it
            console.assert(url === qbf_url, "url should match url from rawstore");
            const unusedCidmultihash = url.split('/')[2];  // Store cid from first block in form of multihash
            const newurl = TransportIPFS.urlFrom(newcid);
            console.assert(url === newurl, "Should round trip");
            urlqbf = url;
            const data = await transport.p_rawfetch(urlqbf);
            console.assert(data.toString() === qbf, "Should fetch block stored above");
            // console.log("TransportIPFS test complete");
            return transport
        } catch(err) {
            console.log("Exception thrown in TransportIPFS.test:", err.message);
            throw err;
        }
    }

}
TransportIPFS.scripts=['ipfs/dist/index.min.js', // window.Ipfs 2.3Mb
    'ipfs-http-client/dist/index.min.js']; // window.IpfsHttpClient
TransportIPFS.requires=['ipfs', 'ipfs-http-client'];


Transports._transportclasses["IPFS"] = TransportIPFS;
// noinspection JSUndefinedPropertyAssignment
exports = module.exports = TransportIPFS;