IPFS: The (Very Slow) Distributed Permanent Web

IPFS: The (Very Slow) Distributed Permanent Web

IPFS stands for InterPlanetary File System, but you could simply consider it as a distributed, permanent, but ridiculously slow, not properly functioning version of web. You could upload any static file and static website to IPFS. And the whole swarm would probably distribute your files to the moon, that might be why IPFS is so fucking slow.

ref:
https://ipfs.io/

Installation

Install on macOS.

$ brew install ipfs

Start your IPFS node.

$ ipfs init
initializing IPFS node at /Users/vinta/.ipfs
generating 2048-bit RSA keypair... done
peer identity: QmfNy1th16zscbpxe8Q2EQdQkNFn7Y3Rp9kGZWL1EQDyw6

$ ipfs daemon

ref:
https://ipfs.io/docs/commands/#ipfs-init
https://ipfs.io/docs/commands/#ipfs-daemon

Furthermore, you might want to run your IPFS node in a Docker container.

# docker-compose.yml
version: "3"
services:
    ipfs:
        image: ipfs/go-ipfs:v0.4.15
        working_dir: /export
        ports:
            - "4001:4001" # Swarm
            - "5001:5001" # web UI
            - "8080:8080" # HTTP proxy
        volumes:
            - "~/.ipfs:/data/ipfs"
            - "~/.ipfs/export:/export"

ref:
https://hub.docker.com/r/ipfs/go-ipfs/

Usage

Show Node Info

$ ipfs id
{
    "ID": "QmfNy1th16zscbpxe8Q2EQdQkNFn7Y3Rp9kGZWL1EQDyw6",
    "PublicKey": "A_LONG_LONG_LONG_KEY,
    "Addresses": [
        "/ip4/127.0.0.1/tcp/4001/ipfs/QmfNy1th16zscbpxe8Q2EQdQkNFn7Y3Rp9kGZWL1EQDyw6",
        "/ip4/172.19.0.2/tcp/4001/ipfs/QmfNy1th16zscbpxe8Q2EQdQkNFn7Y3Rp9kGZWL1EQDyw6"
    ],
    "AgentVersion": "go-ipfs/0.4.14/5db3846",
    "ProtocolVersion": "ipfs/0.1.0"
}

ref:
https://ipfs.io/docs/getting-started/

Add Other Nodes to Your Bootstrap List

This one is from Muzeum, https://muzeum.pro/.

$ ipfs bootstrap add /ip4/52.221.121.238/tcp/4001/ipfs/QmTKYdZDkqHiY24kPynSmKbmRdk7cJxWsvvfvvvZArQ1N9

# you could also connect to a node directly
$ ipfs swarm connect /ip4/52.221.121.238/tcp/4001/ipfs/QmTKYdZDkqHiY24kPynSmKbmRdk7cJxWsvvfvvvZArQ1N9

ref:
https://ipfs.io/docs/commands/#ipfs-bootstrap
https://ipfs.io/docs/commands/#ipfs-swarm

Add Files to IPFS

Every IPFS node's default storage is 10GB, and a single node could only store data it needs, which also means each node only stores a small amount of whole data on IPFS. If there is not enough nodes, your data might be distributed to no one except your own node.

Your content is automatically pinned when you ipfs add it.

$ ipfs add -r mysite
added QmRticJ3P5fnb9GGnUj3U9XMkYvGEnv9AQfk6YmgRhivYA mysite/index.html
added QmY9cxiHqTFoWamkQVkpmmqzBrY3hCBEL2XNu3NtX74Fuu mysite/readme.md
added QmTLhFgeWLacpbiGNYmhchHGQAhfNyDZcLt5akJFFLV89V mysite

If files/folders under the folder change, the hash of the folder changes too.

$ vim mysite/index.html
$ ipfs add -r mysite
added QmQTTe3deLfeULKjPHnQTcyFuCmY5JZiwSTiPT4nSt1KVK mysite/index.html # changed
added QmS85tb3aKQNurFm51FaxtK6NyNei4ej3gDR21baDZXRoU mysite            # changed

ref:
https://ipfs.io/docs/commands/#ipfs-add

Pin Files from IPFS

Pinning means storing IPFS files on local node, and prevent them from getting garbage collected. Also, you could access them much quickly. You only need to do ipfs pin add to pin contents someone else uploaded.

$ ipfs pin add -r --progress /ipns/ipfs.soundscape.net/

$ ipfs pin add --progress /ipns/ipfs.soundscape.net/music_group/index.json
pinned QmZwTEhdjT4MyvEnWndVEJzBjp8zGGZH1cEBpshBQs75rY recursively

$ ipfs pin add --progress /ipns/ipfs.soundscape.net/music_album/index.json
pinned QmSAuGU5xt5SdR2ca2EDgeHFATSrAQhTfTYpYs9K9qmqED recursively

$ ipfs pin add --progress /ipns/ipfs.soundscape.net/music_recording/index.json
pinned QmcTiadA9jRMXx77tydPa6492QJAtjXkKkA4gERaFksy94 recursively

$ ipfs pin add --progress /ipns/ipfs.soundscape.net/music_composition/index.json
pinned QmTfqVaGVRnaPRQgYypGYXUvTK1UcDfK5VWYvU4rwK3m26 recursively

P.S. Sometimes when I ipfs pin add a file which is not on my node, the command just hangs there. I'm not sure why that once I access the file first (through curl or any browser), then ipfs pin add works fine. But it does not make sense: if I already get/access/download the file, I could just ipfs add the file and it would be automatically pinned.

ref:
https://ipfs.io/docs/commands/#ipfs-pin

Get Files

You have several ways to get files or folders from IPFS:

  • ipfs get dir-hash -o readable-dir-name
    • ipfs get QmbMQNcg8TTo5dXZPtuxbns1XVq6cZJaa7vNqZzeJpKwfk -o mysite
  • ipfs get file-hash -o readable-file-name.ext
    • ipfs get Qmd286K6pohQcTKYqnS1YhWrCiS4gz7Xi34sdwMe9USZ7u -o cat.jpg
  • ipfs get /ipfs/dir-hash/path/to/file.txt
    • ipfs get /ipfs/QmYwAPJzv5CZsnA625s3Xf2nemtYgPpHdWEz79ojWnPbdG/readme
  • ipfs get /ipns/example.com/path/to/file.txt
    • ipfs get /ipns/ipfs.soundscape.net/music_group/index.json

You could also access IPFS files through any public gateway:

  • curl https://ipfs.io/ipns/peer-id/path/to/file.txt
    • curl https://ipfs.io/ipns/QmfNy1th16zscbpxe8Q2EQdQkNFn7Y3Rp9kGZWL1EQDyw6/index.html
  • curl https://ipfs.io/ipns/example.com/path/to/file.txt
    • curl https://ipfs.io/ipns/ipfs.soundscape.net/music_group/index.json
  • curl http://127.0.0.1:8080/ipns/example.com/path/to/file.txt
    • curl http://127.0.0.1:8080/ipns/ipfs.soundscape.net/music_group/index.json

Download IPFS objects with ipfs get.

$ ipfs ls QmW2WQi7j6c7UgJTarActp7tDNikE4B2qXtFCfLPdsgaTQ
Qmd286K6pohQcTKYqnS1YhWrCiS4gz7Xi34sdwMe9USZ7u 443362 cat.jpg

# you could get a folder
$ ipfs get QmW2WQi7j6c7UgJTarActp7tDNikE4B2qXtFCfLPdsgaTQ
$ ls QmW2WQi7j6c7UgJTarActp7tDNikE4B2qXtFCfLPdsgaTQ
cat.jpg

# as well as a file
$ ipfs get Qmd286K6pohQcTKYqnS1YhWrCiS4gz7Xi34sdwMe9USZ7u -o cat.jpg

# get files and rename them
$ mkdir -p soundscape/music_group/ soundscape/music_album/ soundscape/music_recording/ soundscape/music_composition/ && \
  ipfs get /ipns/ipfs.soundscape.net/music_group/index.json -o soundscape/music_group/index.json; \
  ipfs get /ipns/ipfs.soundscape.net/music_album/index.json -o soundscape/music_album/index.json; \
  ipfs get /ipns/ipfs.soundscape.net/music_recording/index.json -o soundscape/music_recording/index.json; \
  ipfs get /ipns/ipfs.soundscape.net/music_composition/index.json -o soundscape/music_composition/index.json

# get whole folders
$ ipfs get /ipns/ipfs.soundscape.net/music_group; \
  ipfs get /ipns/ipfs.soundscape.net/music_album; \
  ipfs get /ipns/ipfs.soundscape.net/music_recording; \
  ipfs get /ipns/ipfs.soundscape.net/music_composition

ref:
https://ipfs.io/docs/commands/#ipfs-get
https://discuss.ipfs.io/t/trying-to-better-understand-the-pinning-concept/754

Display IPFS object data with ipfs cat.

$ ipfs cat Qmd286K6pohQcTKYqnS1YhWrCiS4gz7Xi34sdwMe9USZ7u > cat.jpg
$ ipfs cat QmS4ustL54uo8FzR9455qaxZwuMiUhyvMcX9Ba8nUH4uVv/readme

Publish a Website to IPNS

IPNS stands for InterPlanetary Naming System.

Everytime you change files under a folder, the hash of the folder also changes. So you need a static reference which always points to the latest hash of your folder. You could publish your static website (a folder) to IPNS with the static reference, which is your peer ID as well as the hash of your public key.

By default, every IPFS node has only one pair of private and public key. Therefore, you could only publish one folder with your peer ID. But you could add new keypairs through ipfs key gen and publish multiple folders.

$ ipfs add -r mysite
added QmeqHWZgvgx5C7T6DakX75CJDRgAUoSDZayLYrcnAP8Fma mysite/index.html
added QmUtuRphD9rJgRkfxwj7DcyFEAcSeH3Q1fK8nHxxoDiKK5 mysite

$ ipfs name publish QmUtuRphD9rJgRkfxwj7DcyFEAcSeH3Q1fK8nHxxoDiKK5
published to QmfNy1th16zscbpxe8Q2EQdQkNFn7Y3Rp9kGZWL1EQDyw6: /ipfs/QmUtuRphD9rJgRkfxwj7DcyFEAcSeH3Q1fK8nHxxoDiKK5

$ ipfs name resolve QmfNy1th16zscbpxe8Q2EQdQkNFn7Y3Rp9kGZWL1EQDyw6
/ipfs/QmUtuRphD9rJgRkfxwj7DcyFEAcSeH3Q1fK8nHxxoDiKK5

Click following links to see contents.

After you change something, publish it again with new hash.

$ vim mysite/index.html
$ ipfs add -r mysite
added QmNjbhdks8RUgDt6QiNFe5QGe2HrbCsq5FKda9D9hLVkkU mysite/index.html # changed
added QmbMQNcg8TTo5dXZPtuxbns1XVq6cZJaa7vNqZzeJpKwfk mysite            # changed

$ ipfs name publish QmbMQNcg8TTo5dXZPtuxbns1XVq6cZJaa7vNqZzeJpKwfk
published to QmfNy1th16zscbpxe8Q2EQdQkNFn7Y3Rp9kGZWL1EQDyw6: /ipfs/QmbMQNcg8TTo5dXZPtuxbns1XVq6cZJaa7vNqZzeJpKwfk

ref:
https://ipfs.io/docs/commands/#ipfs-name

Create a Domain Name Alias for Your Peer ID

The hash is not very friendly for humans. Fortunately, you could and probably should associate a domain name with your peer ID.

First, you need to add a TXT record whose value is dnslink=/ipns/YOUR_PEER_ID to your domain name. In the following article, we assume the domain name you choose is ipfs.kittenphile.com.

$ dig +short TXT ipfs.kittenphile.com
"dnslink=/ipns/QmfNy1th16zscbpxe8Q2EQdQkNFn7Y3Rp9kGZWL1EQDyw6"

$ ipfs name resolve -r ipfs.kittenphile.com
/ipfs/QmaE2DcNxGjPGPfzfTQuTBTW9D57abVSv319WqC89Av1y1

Click following links to see contents.

ref:
https://ipfs.io/docs/examples/example-viewer/example#../websites/README.md
https://hackernoon.com/ten-terrible-attempts-to-make-the-inter-planetary-file-system-human-friendly-e4e95df0c6fa

Public Gateway

If you have a public gateway and people retrieve files through it. Your public gateway fetches and stores the data, but it doesn't pin them. Files get removed with the next garbage collection run.

ref:
https://discuss.ipfs.io/t/public-facing-gateway-and-pinning/449

你都去哪裡看技術文章?

你都去哪裡看技術文章?

因為前陣子跟朋友們一起弄了一個技術週刊:CodeTengu Weekly 碼天狗週刊,每個禮拜在考慮要放哪些內容的時候,突然覺得:「你都去哪裡看技術文章?」或許也會是個有價值而且實用的主題,所以乾脆就來跟大家分享一下,我覺得不錯的每日資訊來源。

你可以訂閱的週報

五花八門

程式語言

資料庫

DevOps

Machine Learning

你可以瀏覽的網站

如果要推薦值得一看的網站或網誌,說八年都說不完,而且現在大家也都不用 RSS reader 了(真的很可惜,明明就很方便),這裡就只提幾個「內容聚合網站」(news aggregator)。你可以在這些網站上 follow 特定的主題,例如 Python、Golang、Apache Cassandra、Docker 之類的,他們就會自動把相關的文章推送給你,比較特別的是,網站還會根據你的個人喜好和你在 Twitter 上關注的對象來調整推送給你的內容。

我最早用過這一類的服務是 Zite,但是直到它老是推薦「印度一條六公尺的巨蟒(Python)吞食了一個人類小孩」的新聞給我之後,我就把它刪掉了。雖然說 Zite 已經被收購,整合進 Flipboard 裡,但是我已經對它沒信心啦。

2015.09.06 更新:

你可以關注的人

以下列出的是許多喜歡在 Twitter 上分享技術文章而且推文頻率又比較高的開發者:

出沒於 Twitter

出沒於 Facebook

Computer names for Sci-Fi maniac developers

科幻迷的 hostname 列表

  • ADA (Anubis Zone of the Enders)
  • Asurada (Future GPX Cyber Formula)
  • Deep Thought (The Hitchhiker's Guide to the Galaxy)
  • EDI (Mass Effect)
  • EVA-00 (Neon Genesis Evangelion)
  • EVA-01 (Neon Genesis Evangelion)
  • EVA-02 (Neon Genesis Evangelion)
  • GERTY (Moon)
  • GLaDOS (Portal)
  • HAL 9000 (2001: A Space Odyssey)
  • Jane (Ender's Game)
  • JARVIS (Iron Man)
  • KOS-MOS (Xenosaga)
  • MAGI (Neon Genesis Evangelion)
  • Melchizedek (Gunnm Last Order)
  • Mike (The Moon Is a Harsh Mistress)
  • Pip-Boy 3000 (Fallout)
  • Project 2501 (Ghost in the Shell)
  • Skynet (The Terminator)
  • Tachikoma (Ghost in the Shell)
  • TARS (Interstellar)
  • TechnoCore (Hyperion)
  • VIKI (I, Robot)
  • Wheatley (Portal)

ref:
https://www.wikiwand.com/en/List_of_fictional_computers
https://www.wikiwand.com/en/Artificial_intelligence_in_fiction

MkDocs: Deploy your Markdown documents on GitHub Pages

MkDocs: Deploy your Markdown documents on GitHub Pages

MkDocs is a static site generator that builds modern webpages based on your Markdown documents and a simple YAML file.

ref:
https://www.mkdocs.org/

Here is the website which is generated by MkDocs in this post:
https://awesome-python.com/
https://github.com/vinta/awesome-python

Installation

$ pip install mkdocs

Configuration

in mkdocs.yml

site_name: Awesome Python
site_url: https://awesome-python.com
site_description: A curated list of awesome Python frameworks, libraries and software
site_author: Vinta Chen
repo_url: https://github.com/vinta/awesome-python
theme: flatly
google_analytics: ['UA-510626-7', 'auto']
pages:
  - "Life is short, you need Python.": "index.md"

There are more themes:

in Makefile

site_install:
    pip install mkdocs==0.16.3
    pip install mkdocs-material==1.12.2

site_link:
    ln -sf $(CURDIR)/README.md $(CURDIR)/docs/index.md

site_preview: site_link
    mkdocs serve

site_deploy: site_link
    mkdocs gh-deploy --clean

Custom Domain for GitHub Pages

in docs/CNAME

awesome-python.com

After deploying your GitHub Page, just pointing your domain to 192.30.252.153 with an A DNS record.

ref:
https://help.github.com/articles/setting-up-an-apex-domain/#configuring-a-records-with-your-dns-provider

Read and write files in Go

Reading file line by line

如果要一行一行地讀
建議用 bufio.Scanner
但是 Scanner 有個缺點
就是一行太長(超過 64K)的時候會出現 bufio.Scanner: token too long 的錯誤
這時候還是得用 bufio.Reader

fin, err := os.Open(path)
if err != nil {
    fmt.Println(err)
}
defer fin.Close()

scanner := bufio.NewScanner(fin)
for scanner.Scan() {
    line := scanner.Text()
    fmt.Fprintln(os.Stdin, line)
}

if err := scanner.Err(); err != nil {
    fmt.Fprintln(os.Stderr, err)
}

If you know the maximum length of the tokens you will be reading, copy the bufio.Scanner code into your project and change the const MaxScanTokenSize value.

ref:
http://stackoverflow.com/questions/6141604/go-readline-string
http://stackoverflow.com/questions/1821811/how-to-read-write-from-to-file
http://stackoverflow.com/questions/8757389/reading-file-line-by-line-in-go
http://stackoverflow.com/questions/5884154/golang-read-text-file-into-string-array-and-write
https://github.com/polaris1119/The-Golang-Standard-Library-by-Example/blob/master/chapter01/01.4.md

bufio
https://golang.org/pkg/bufio/
https://golang.org/pkg/bufio/#Scanner

Reading and writing file line by line

fmt.Fprintln(writer, line)bw.WriteString(line) 還要快

func FileSpacing(filename string, w io.Writer) (err error) {
    fr, err := os.Open(filename)
    if err != nil {
        return err
    }
    defer fr.Close()

    br := bufio.NewReader(fr)
    bw := bufio.NewWriter(w)

    for {
        line, err := br.ReadString('\n')
        if err == nil {
            fmt.Fprint(bw, TextSpacing(line))
        } else {
            if err == io.EOF {
                fmt.Fprint(bw, TextSpacing(line))
                break
            }
            return err
        }
    }
    defer bw.Flush()

    return nil
}

Copy a file

fin, _ := os.Open("source.txt")
fout, _ := os.Create("destination.txt")

io.Copy(fout, fin)

defer fout.Close()
defer fin.Close()

ref:
http://stackoverflow.com/questions/23272663/transfer-a-big-file-in-golang
http://golang.org/pkg/io/#Copy

Compute MD5 of a file

func md5Of(filename string) string {
    var result []byte

    file, err := os.Open(filename)
    checkError(err)
    defer file.Close()

    hash := md5.New()
    _, err = io.Copy(hash, file)
    checkError(err)

    checksum := hex.EncodeToString(hash.Sum(result))

    return checksum
}

ref:
http://stackoverflow.com/questions/29505089/how-can-i-compare-two-files-in-golang