path: root/cmd/swarm/feeds.go

// Copyright 2016 The go-ethereum Authors
// This file is part of go-ethereum.
//
// go-ethereum is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// go-ethereum is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with go-ethereum. If not, see <http://www.gnu.org/licenses/>.

// Command feed allows the user to create and update signed Swarm feeds
package main

import (
    "fmt"
    "strings"

    "github.com/dexon-foundation/dexon/common"
    "github.com/dexon-foundation/dexon/common/hexutil"
    "github.com/dexon-foundation/dexon/crypto"

    "github.com/dexon-foundation/dexon/cmd/utils"
    swarm "github.com/dexon-foundation/dexon/swarm/api/client"
    "github.com/dexon-foundation/dexon/swarm/storage/feed"
    "gopkg.in/urfave/cli.v1"
)

var feedCommand = cli.Command{
    CustomHelpTemplate: helpTemplate,
    Name:               "feed",
    Usage:              "(Advanced) Create and update Swarm Feeds",
    ArgsUsage:          "<create|update|info>",
    Description:        "Works with Swarm Feeds",
    Subcommands: []cli.Command{
        {
            Action:             feedCreateManifest,
            CustomHelpTemplate: helpTemplate,
            Name:               "create",
            Usage:              "creates and publishes a new feed manifest",
            Description: `creates and publishes a new feed manifest pointing to a specified user's updates about a particular topic.
                    The feed topic can be built in the following ways:
                    * use --topic to set the topic to an arbitrary binary hex string.
                    * use --name to set the topic to a human-readable name.
                        For example --name could be set to "profile-picture", meaning this feed allows to get this user's current profile picture.
                    * use both --topic and --name to create named subtopics. 
                        For example, --topic could be set to an Ethereum contract address and --name could be set to "comments", meaning
                        this feed tracks a discussion about that contract.
                    The --user flag allows to have this manifest refer to a user other than yourself. If not specified,
                    it will then default to your local account (--bzzaccount)`,
            Flags: []cli.Flag{SwarmFeedNameFlag, SwarmFeedTopicFlag, SwarmFeedUserFlag},
        },
        {
            Action:             feedUpdate,
            CustomHelpTemplate: helpTemplate,
            Name:               "update",
            Usage:              "updates the content of an existing Swarm Feed",
            ArgsUsage:          "<0x Hex data>",
            Description: `publishes a new update on the specified topic
                    The feed topic can be built in the following ways:
                    * use --topic to set the topic to an arbitrary binary hex string.
                    * use --name to set the topic to a human-readable name.
                        For example --name could be set to "profile-picture", meaning this feed allows to get this user's current profile picture.
                    * use both --topic and --name to create named subtopics. 
                        For example, --topic could be set to an Ethereum contract address and --name could be set to "comments", meaning
                        this feed tracks a discussion about that contract.
                    
                    If you have a manifest, you can specify it with --manifest to refer to the feed,
                    instead of using --topic / --name
                    `,
            Flags: []cli.Flag{SwarmFeedManifestFlag, SwarmFeedNameFlag, SwarmFeedTopicFlag},
        },
        {
            Action:             feedInfo,
            CustomHelpTemplate: helpTemplate,
            Name:               "info",
            Usage:              "obtains information about an existing Swarm feed",
            Description: `obtains information about an existing Swarm feed
                    The topic can be specified directly with the --topic flag as an hex string
                    If no topic is specified, the default topic (zero) will be used
                    The --name flag can be used to specify subtopics with a specific name.
                    The --user flag allows to refer to a user other than yourself. If not specified,
                    it will then default to your local account (--bzzaccount)
                    If you have a manifest, you can specify it with --manifest instead of --topic / --name / ---user
                    to refer to the feed`,
            Flags: []cli.Flag{SwarmFeedManifestFlag, SwarmFeedNameFlag, SwarmFeedTopicFlag, SwarmFeedUserFlag},
        },
    },
}

func NewGenericSigner(ctx *cli.Context) feed.Signer {
    return feed.NewGenericSigner(getPrivKey(ctx))
}

func getTopic(ctx *cli.Context) (topic feed.Topic) {
    var name = ctx.String(SwarmFeedNameFlag.Name)
    var relatedTopic = ctx.String(SwarmFeedTopicFlag.Name)
    var relatedTopicBytes []byte
    var err error

    if relatedTopic != "" {
        relatedTopicBytes, err = hexutil.Decode(relatedTopic)
        if err != nil {
            utils.Fatalf("Error parsing topic: %s", err)
        }
    }

    topic, err = feed.NewTopic(name, relatedTopicBytes)
    if err != nil {
        utils.Fatalf("Error parsing topic: %s", err)
    }
    return topic
}

// swarm feed create <frequency> [--name <name>] [--data <0x Hexdata> [--multihash=false]]
// swarm feed update <Manifest Address or ENS domain> <0x Hexdata> [--multihash=false]
// swarm feed info <Manifest Address or ENS domain>

func feedCreateManifest(ctx *cli.Context) {
    var (
        bzzapi = strings.TrimRight(ctx.GlobalString(SwarmApiFlag.Name), "/")
        client = swarm.NewClient(bzzapi)
    )

    newFeedUpdateRequest := feed.NewFirstRequest(getTopic(ctx))
    newFeedUpdateRequest.Feed.User = feedGetUser(ctx)

    manifestAddress, err := client.CreateFeedWithManifest(newFeedUpdateRequest)
    if err != nil {
        utils.Fatalf("Error creating feed manifest: %s", err.Error())
        return
    }
    fmt.Println(manifestAddress) // output manifest address to the user in a single line (useful for other commands to pick up)

}

func feedUpdate(ctx *cli.Context) {
    args := ctx.Args()

    var (
        bzzapi                  = strings.TrimRight(ctx.GlobalString(SwarmApiFlag.Name), "/")
        client                  = swarm.NewClient(bzzapi)
        manifestAddressOrDomain = ctx.String(SwarmFeedManifestFlag.Name)
    )

    if len(args) < 1 {
        fmt.Println("Incorrect number of arguments")
        cli.ShowCommandHelpAndExit(ctx, "update", 1)
        return
    }

    signer := NewGenericSigner(ctx)

    data, err := hexutil.Decode(args[0])
    if err != nil {
        utils.Fatalf("Error parsing data: %s", err.Error())
        return
    }

    var updateRequest *feed.Request
    var query *feed.Query

    if manifestAddressOrDomain == "" {
        query = new(feed.Query)
        query.User = signer.Address()
        query.Topic = getTopic(ctx)
    }

    // Retrieve a feed update request
    updateRequest, err = client.GetFeedRequest(query, manifestAddressOrDomain)
    if err != nil {
        utils.Fatalf("Error retrieving feed status: %s", err.Error())
    }

    // Check that the provided signer matches the request to sign
    if updateRequest.User != signer.Address() {
        utils.Fatalf("Signer address does not match the update request")
    }

    // set the new data
    updateRequest.SetData(data)

    // sign update
    if err = updateRequest.Sign(signer); err != nil {
        utils.Fatalf("Error signing feed update: %s", err.Error())
    }

    // post update
    err = client.UpdateFeed(updateRequest)
    if err != nil {
        utils.Fatalf("Error updating feed: %s", err.Error())
        return
    }
}

func feedInfo(ctx *cli.Context) {
    var (
        bzzapi                  = strings.TrimRight(ctx.GlobalString(SwarmApiFlag.Name), "/")
        client                  = swarm.NewClient(bzzapi)
        manifestAddressOrDomain = ctx.String(SwarmFeedManifestFlag.Name)
    )

    var query *feed.Query
    if manifestAddressOrDomain == "" {
        query = new(feed.Query)
        query.Topic = getTopic(ctx)
        query.User = feedGetUser(ctx)
    }

    metadata, err := client.GetFeedRequest(query, manifestAddressOrDomain)
    if err != nil {
        utils.Fatalf("Error retrieving feed metadata: %s", err.Error())
        return
    }
    encodedMetadata, err := metadata.MarshalJSON()
    if err != nil {
        utils.Fatalf("Error encoding metadata to JSON for display:%s", err)
    }
    fmt.Println(string(encodedMetadata))
}

func feedGetUser(ctx *cli.Context) common.Address {
    var user = ctx.String(SwarmFeedUserFlag.Name)
    if user != "" {
        return common.HexToAddress(user)
    }
    pk := getPrivKey(ctx)
    if pk == nil {
        utils.Fatalf("Cannot read private key. Must specify --user or --bzzaccount")
    }
    return crypto.PubkeyToAddress(pk.PublicKey)

}