How to Run IPFS with Embark Platform Demo

I'm new to blockchaining, I've learned from various sources that we can use the embark framework together with IPFS to make DApp creation easier.

I started by running all instructions from the gigaub embark page

I ran the following command to create a demo of all features

$ embark demo
$ cd embark_demo

      

then run emark emulator

$ embark simulator

      

everything works fine, even on the localhost page and I can get and set the int values. Blockchains with Embark

However, I cannot use the IPFS tab on the page? It gives the following error: "The node being used does not support IPFS. Make sure CORS is configured for the IPFS node."

However, I successfully started the IPFS Daemon

I also uncommented this line from my index.js file

EmbarkJS.Storage.setProvider('ipfs',{server: 'localhost', port: '5001'})

      

index.js

/*globals $, SimpleStorage, document*/

var addToLog = function(id, txt) {
  $(id + " .logs").append("<br>" + txt);
};

// ===========================
// Blockchain example
// ===========================
$(document).ready(function() {

  $("#blockchain button.set").click(function() {
    var value = parseInt($("#blockchain input.text").val(), 10);
    SimpleStorage.set(value);
    addToLog("#blockchain", "SimpleStorage.set(" + value + ")");
  });

  $("#blockchain button.get").click(function() {
    SimpleStorage.get().then(function(value) {
      $("#blockchain .value").html(value.toNumber());
    });
    addToLog("#blockchain", "SimpleStorage.get()");
  });

});

// ===========================
// Storage (IPFS) example
// ===========================
$(document).ready(function() {
  //var ipfs = window.IpfsApi('localhost', '5001');
  var ipfs = ipfsAPI({
    host: 'localhost',
    port: '5001',
    protocol: 'http'
  });
  // automatic set if config/storage.json has "enabled": true and "provider": "ipfs"
  EmbarkJS.Storage.setProvider('ipfs', {
    server: 'localhost',
    port: '5001'
  })

  $("#storage .error").hide();
  EmbarkJS.Storage.ipfsConnection.ping()
    .then(function() {
      $("#status-storage").addClass('status-online');
      $("#storage-controls").show();
    })
    .catch(function(err) {
      if (err) {
        console.log("IPFS Connection Error => " + err.message);
        $("#storage .error").show();
        $("#status-storage").addClass('status-offline');
        $("#storage-controls").hide();
      }
    });

  $("#storage button.setIpfsText").click(function() {
    var value = $("#storage input.ipfsText").val();
    EmbarkJS.Storage.saveText(value).then(function(hash) {
      $("span.textHash").html(hash);
      $("input.textHash").val(hash);
    });
    addToLog("#storage", "EmbarkJS.Storage.saveText('" + value + "').then(function(hash) { })");
  });

  $("#storage button.loadIpfsHash").click(function() {
    var value = $("#storage input.textHash").val();
    EmbarkJS.Storage.get(value).then(function(content) {
      $("span.ipfsText").html(content);
    });
    addToLog("#storage", "EmbarkJS.Storage.get('" + value + "').then(function(content) { })");
  });

  $("#storage button.uploadFile").click(function() {
    var input = $("#storage input[type=file]");
    EmbarkJS.Storage.uploadFile(input).then(function(hash) {
      $("span.fileIpfsHash").html(hash);
      $("input.fileIpfsHash").val(hash);
    });
    addToLog("#storage", "EmbarkJS.Storage.uploadFile($('input[type=file]')).then(function(hash) { })");
  });

  $("#storage button.loadIpfsFile").click(function() {
    var hash = $("#storage input.fileIpfsHash").val();
    var url = EmbarkJS.Storage.getUrl(hash);
    var link = '<a href="' + url + '" target="_blank">' + url + '</a>';
    $("span.ipfsFileUrl").html(link);
    $(".ipfsImage").attr('src', url);
    addToLog("#storage", "EmbarkJS.Storage.getUrl('" + hash + "')");
  });

});

// ===========================
// Communication (Whisper) example
// ===========================
$(document).ready(function() {

  $("#communication .error").hide();
  web3.version.getWhisper(function(err, res) {
    if (err) {
      $("#communication .error").show();
      $("#communication-controls").hide(); +
      $("#status-communication").addClass('status-offline');
    } else {
      EmbarkJS.Messages.setProvider('whisper');
      $("#status-communication").addClass('status-online');
    }
  });

  $("#communication button.listenToChannel").click(function() {
    var channel = $("#communication .listen input.channel").val();
    $("#communication #subscribeList").append("<br> subscribed to " + channel + " now try sending a message");
    EmbarkJS.Messages.listenTo({
      topic: [channel]
    }).then(function(message) {
      $("#communication #messagesList").append("<br> channel: " + channel + " message: " + message);
    });
    addToLog("#communication", "EmbarkJS.Messages.listenTo({topic: ['" + channel + "']}).then(function(message) {})");
  });

  $("#communication button.sendMessage").click(function() {
    var channel = $("#communication .send input.channel").val();
    var message = $("#communication .send input.message").val();
    EmbarkJS.Messages.sendMessage({
      topic: channel,
      data: message
    });
    addToLog("#communication", "EmbarkJS.Messages.sendMessage({topic: '" + channel + "', data: '" + message + "'})");
  });

});
      

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index.html

<html>

<head>
  <title>Embark - SimpleStorage Demo</title>
  <link rel="stylesheet" href="css/app.css">
  <script src="js/app.js"></script>
</head>

<body class="container">
  <h3>Embark - Usage Example</h3>

  <ul class="nav nav-tabs" role="tablist" id="myTabs">
    <li role="presentation" class="active"><a href="#blockchain" aria-controls="blockchain" role="tab" data-toggle="tab">Blockchain</a></li>
    <li role="presentation"><a href="#storage" aria-controls="storage" role="tab" data-toggle="tab">Decentralized Storage (IPFS)<span class="pull-right" id="status-storage"></a></li>
    <li role="presentation"><a href="#communication" aria-controls="communication" role="tab" data-toggle="tab">P2P communication (Whisper/Orbit)<span class="pull-right" id="status-communication"></span></a></li>
  </ul>

  <div class="tab-content">
    <div role="tabpanel" class="tab-pane active" id="blockchain">
      <h3> 1. Set the value in the blockchain</h3>
      <div class="form-group form-inline">
        <input type="text" class="text form-control" value="10">
        <button class="set btn btn-primary">Set Value</button>
        <p>Once you set the value, the transaction will need to be mined and then the value will be updated on the blockchain.</p>
      </div>

      <h3> 2. Get the current value</h3>
      <div class="form-group">
        <div>
          current value is <span class="value"></span>
        </div>
        <button class="get btn btn-primary">Get Value</button>
        <p>Click the button to get the current value. The initial value is 100.</p>
      </div>

      <h3> 3. Contract Calls </h3>
      <p>Javascript calls being made: </p>
      <div class="logs">
      </div>
    </div>
    <div role="tabpanel" class="tab-pane" id="storage">
      <div class="error alert alert-danger" role="alert">The node you are using does not support IPFS. Please ensure <a href="https://github.com/ipfs/js-ipfs-api#cors" target="_blank">CORS</a> is setup for the IPFS node.</div>
      <div id="storage-controls">

        <h3>Save text to IPFS</h3>
        <div class="form-group form-inline">
          <input type="text" class="ipfsText text form-control" value="hello world!">
          <button class="setIpfsText btn btn-primary">Save</button>
          <p>generated Hash: <span class="textHash"></span></p>
        </div>

        <h3>Load text from IPFS given an hash</h3>
        <div class="form-group form-inline">
          <input type="text" class="textHash text form-control" size="60">
          <button class="loadIpfsHash set btn btn-primary">Load</button>
          <p>result: <span class="ipfsText"></span></p>
        </div>

        <h3>upload file to ipfs</h3>
        <div class="form-group form-inline">
          <input type="file" class="form-control">
          <button class="uploadFile set btn btn-primary">upload</button>
          <p>generated hash: <span class="fileIpfsHash"></span></p>
        </div>

        <h3>Get file or image from ipfs</h3>
        <div class="form-group form-inline">
          <input type="text" class="fileIpfsHash form-control" size="60">
          <button class="loadIpfsFile set btn btn-primary">Load</button>
          <p>file available at: <span class="ipfsFileUrl"></span></p>
          <p><img class="ipfsImage" src=""></p>
        </div>

        <p>Javascript calls being made: </p>
        <div class="logs">
          <br> EmbarkJS.Storage.setProvider('ipfs',{server: 'localhost', port: '5001'})
        </div>
      </div>
    </div>
    <div role="tabpanel" class="tab-pane" id="communication">
      <div class="error alert alert-danger" role="alert">The node you are using does not support Whisper</div>
      <div id="communication-controls">
        <h3>Listen To channel</h3>
        <div class="form-group form-inline listen">
          <input type="text" class="channel text form-control" placeholder="channel">
          <button class="listenToChannel set btn btn-primary">Start Listening</button>
          <div id="subscribeList"></div>
          <p>messages received:
            <p>
              <div id="messagesList"></div>
        </div>

        <h3>Send Message</h3>
        <div class="form-group form-inline send">
          <input type="text" class="channel text form-control" placeholder="channel">
          <input type="text" class="message text form-control" placeholder="message">
          <button class="sendMessage set btn btn-primary">Send Message</button>
        </div>

        <p>Javascript calls being made: </p>
        <div class="logs">
          <br> EmbarkJS.Messages.setProvider('whisper')
        </div>
      </div>
    </div>
  </div>

</body>

</html>
      

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Solidarity Contract:

pragma solidity ^ 0.4 .7;
contract SimpleStorage {
  uint public storedData;

  function SimpleStorage(uint initialValue) {
    storedData = initialValue;
  }

  function set(uint x) {
    storedData = x;
  }

  function get() constant returns(uint retVal) {
    return storedData;
  }

}
      

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The output is as follows: none of the buttons work, please tell me what is wrong: IPFS tab

I have also tried following commands according to other websites with little success

$ ipfs config --json API.HTTPHeaders.Access-Control-Allow-Origin "[*]"
$ ipfs config --json API.HTTPHeaders.Access-Control-Allow-Credentials "[\"true\"]"
$ ipfs config --json API.HTTPHeaders.Access-Control-Allow-Methods "[\"PUT\", \"POST\", \"GET\"]"

      

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3 answers


I decided. Using



ipfs config --json API.HTTPHeaders.Access-Control-Allow-Credentials '["true"]'
ipfs config --json API.HTTPHeaders.Access-Control-Allow-Methods '["PUT", "POST", "GET"]'
ipfs config --json API.HTTPHeaders.Access-Control-Allow-Headers '["Authorization"]'
ipfs config --json API.HTTPHeaders.Access-Control-Expose-Headers '["Location"]'
ipfs config --json API.HTTPHeaders.Access-Control-Allow-Origin '["*"]'

      

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I don't know exactly which one worked for me, as I did this before killing and restarting embark simulator

and embark run

, however, running these two commands seemed to fix the problem:

ipfs config --json API.HTTPHeaders.Access-Control-Allow-Origin "[\"*\"]"
ipfs config --json API.HTTPHeaders.Access-Control-Allow-Origin "[\"http://localhost:8000\"]"

      



Also I have no idea if this command * works, so use it at your own risk!

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Remember to start ipfs (in daemon mode) $ ipfs daemon

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