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Ethereum RLP

RLP (Recursive Length Prefix) is the main encoding method used to serialize objects in Ethereum. Usages include generate raw transaction, data storage.

RLP Encoder

<?php 
use kornrunner\Keccak;

/* due to version conflict with the one in vendor/, so i manually clone this package to new folder and include without autoload*/
include_once("../libraries/web3p/rlp/Types/Str.php");
include_once("../libraries/web3p/rlp/Types/Numeric.php");
include_once("../libraries/web3p/rlp/RLP.php");

include_once("html_iframe_header.php");

use Web3p\RLP\RLP;

$result = '';
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
	try {
		$rlp = new RLP;
		
		$firstTag = substr($_POST['string'], 0, 1);
		$lastTag  = substr($_POST['string'], -1);
		
		if ($firstTag == '[' AND $lastTag == ']') {
			$toEncode = json_decode($_POST['string'],true);
		
			if (json_last_error() !== JSON_ERROR_NONE) {
				throw new Exception("Invalid JSON-ARRAY string.");
			}
		} else {
			
			//auto cast if integer or float is detected
			
			if (ctype_digit($_POST['string'])) {
				$toEncode = (int)$_POST['string'];
			} else if (is_numeric($_POST['string'])) {
				$toEncode = (float)$_POST['string'];
			} else {
				$toEncode = $_POST['string'];
			}
		}
		$result = $rlp->encode($toEncode);
		
	} catch (Exception $e) {
        $errmsg .= "Problem found. " . $e->getMessage();
    }
}

if ($errmsg) {
?>
	<div class="alert alert-danger">
		<strong>Error!</strong> <?php echo $errmsg?>
	</div>
<?php
}

if ($result) {
?>
	<div class="alert alert-success">
		<?php echo $result;?>
	</div>
<?php
}
?>
<form action='' method='post'>
	<div class="form-group">
		<label for="string">Data To Encode:</label>
		<textarea class="form-control" type='text' name='string' id='string' rows=10><?php echo $_POST['string']?></textarea>
		<small>
			<ol style="padding-left: 0; list-style: inside decimal;">
				<li>
					To encode array, JSON-ARRAY serialized string must be applied and start with '[' and end with ']'.
				</li>
				
				<li>
					Numeric number will be casted to integer or float.
				</li>
			</ol>
		</small>
	</div>

	<input type='submit' class="btn btn-success btn-block"/>
</form>
<?php 
include_once("html_iframe_footer.php");
go/eth_rlp_encoder.go
package main

import(
	_ "fmt"
	"github.com/ethereum/go-ethereum/rlp"
	"github.com/ethereum/go-ethereum/common/hexutil"
	"encoding/json"
	"strings"
	"math"
)

func rlpEncode(dataJson string) (map[string]string, error) {
	
	response := make(map[string]string)
	
	var thisError error	
	var arrJson []interface{}
	var rlpBytes []byte = []byte{}
	
	if thisError = json.Unmarshal([]byte(dataJson),&arrJson); thisError == nil {
		
		for k, v := range arrJson {
			
			switch v.(type) {
				case string:
					
					if strings.HasPrefix(v.(string), "0x") {
						arrJson[k], _ = hexutil.Decode(v.(string))
					}
				case float64:
					if (v.(float64) / math.Round(v.(float64))) == 1 {
						//convert if it is an integer
						arrJson[k] = uint64(arrJson[k].(float64))
					} 
				default:
				
			}
		}
		
		if rlpBytes, thisError = rlp.EncodeToBytes(arrJson); thisError==nil {
			response["rlpHex"] = hexutil.Encode(rlpBytes)
		}
		
	} 
	
	return response,thisError
}
go/templates/eth_rlp_encoder.html
{{ template "html_iframe_header.html" .}}

{{if .error}}
	<div class="alert alert-danger">
        <strong>Error!</strong> {{ .error }}
    </div>
{{else if .rlpHex}}
	<div class="alert alert-success">
		{{.rlpHex}}
	</div>
{{end}}

<form action='' method='post'>
	<div class="form-group">
		<label for="string">Data To Encode:</label>
		<textarea class="form-control" type='text' name='string' id='string' rows=10>{{.string}}</textarea>
		<small>
			<ol style="padding-left: 0; list-style: inside decimal;">
				<li>
					To encode array, JSON-ARRAY serialized string must be applied and start with '[' and end with ']'.
				</li>
				
				<li>
					Numeric number will be casted to integer or float.
				</li>
			</ol>
		</small>
	</div>

	<input type='submit' class="btn btn-success btn-block"/>
</form>

{{ template "html_iframe_footer.html" .}}

RLP Decoder

<?php 
use kornrunner\Keccak;

/* due to version conflict with the one in vendor/, so i manually clone this package to new folder and include without autoload*/
include_once("../libraries/web3p/rlp/Types/Str.php");
include_once("../libraries/web3p/rlp/Types/Numeric.php");
include_once("../libraries/web3p/rlp/RLP.php");

include_once("html_iframe_header.php");

use Web3p\RLP\RLP;

$result = '';
if ($_SERVER['REQUEST_METHOD'] == 'POST') {
	try {
		$rlp = new RLP;
		$rlpedStr = ltrim($_POST['rlped_string'], "0x");
		$result = $rlp->decode("0x" . $rlpedStr);
		
	} catch (Exception $e) {
        $errmsg .= "Problem found. " . $e->getMessage();
    }
}

if ($errmsg) {
?>
	<div class="alert alert-danger">
		<strong>Error!</strong> <?php echo $errmsg?>
	</div>
<?php
}

if ($result) {

	if (is_array($result)) {
?>
		<div class="alert alert-success">Result is in Array</div>
<?php
		echo "<pre>";
		var_dump($result);
		echo "</pre>";
	} else {
?>
		<div class="alert alert-success">
			<?php echo $result;?>
		</div>
<?php	
	}
}
?>
<form action='' method='post'>
	<div class="form-group">
		<label for="rlped_string">Data To Decode:</label>
		<input class="form-control" type='text' name='rlped_string' id='rlped_string' rows=10 value="<?php echo $_POST['rlped_string']?>">
		
		<small>
			Result is in HEX. Below is conversion tool from HEX to your desired data types.
			<ol style="padding-left: 0; list-style: inside decimal;">
				<li><a href="https://www.rapidtables.com/convert/number/hex-to-decimal.html" target="blank">HEX To Decimal</a></li>
				<li><a href="http://string-functions.com/hex-string.aspx" target="blank">HEX To String</a></li>
			</ol>
		</small>
			
			
		
	</div>

	<input type='submit' class="btn btn-success btn-block"/>
</form>
<?php 
include_once("html_iframe_footer.php");







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