nodemcu-firmware/docs/modules/encoder.md

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# encoder Module
| Since | Origin / Contributor | Maintainer | Source |
| :----- | :-------------------- | :---------- | :------ |
| 2016-02-26 | [Terry Ellison](https://github.com/TerryE) | [Terry Ellison](https://github.com/TerryE) | [encoder.c](../../components/modules/encoder.c)|
The encoder modules provides various functions for encoding and decoding byte data.
## encoder.toBase64()
Provides a Base64 representation of a (binary) Lua string.
#### Syntax
`b64 = encoder.toBase64(binary)`
#### Parameters
`binary` input string to Base64 encode
#### Return
A Base64 encoded string.
#### Example
```lua
print(encoder.toBase64(crypto.hash("sha1","abc")))
```
## encoder.fromBase64()
Decodes a Base64 representation of a (binary) Lua string back into the original string. An error is
thrown if the string is not a valid base64 encoding.
#### Syntax
`binary_string = encoder.toBase64(b64)`
#### Parameters
`b64` Base64 encoded input string
#### Return
The decoded Lua (binary) string.
#### Example
```lua
print(encoder.fromBase64(encoder.toBase64("hello world")))
```
## encoder.toHex()
Provides an ASCII hex representation of a (binary) Lua string. Each byte in the input string is
represented as two hex characters in the output.
#### Syntax
`hexstr = encoder.toHex(binary)`
#### Parameters
`binary` input string to get hex representation for
#### Returns
An ASCII hex string.
#### Example
```lua
print(encoder.toHex(crypto.hash("sha1","abc")))
```
## encoder.fromHex()
Returns the Lua binary string decode of a ASCII hex string. Each byte in the output string is
represented as two hex characters in the input. An error is thrown if the string is not a
valid base64 encoding.
#### Syntax
`binary = encoder.fromHex(hexstr)`
#### Parameters
`hexstr` An ASCII hex string.
#### Returns
Decoded string of hex representation.
#### Example
```lua
print(encoder.fromHex("6a6a6a"))
```