How to set RangeOfInteger

[ChrisKays]

Hi,

Your Airprint.NET helped me a lot writing my own server App and i understand that this a client App that send a job to a printer. Because i'm writing a server app i need to reply to the client that send request. Among the responses that i need to send is the Copies-Supported Attribute which is defined as RangeOfInteger (https://tools.ietf.org/html/rfc2911).

here's an example of how i set other attributes:

• this.Group[AttrGroups.PrinterTag].Add(new Attribute(Tag.Keyword, "sides-supported", "one-sided"));
  The above example set the sides-supported.
  I can also use the same structure to set other value such as copie-default with Tag value = Integer
  But i would also like to set copies-supported attributes, How do i set such value which has value attribute = RangeOfInteger.

Thanks for the help in advance.

[mj-hd]

This implementation only supports reading of RangeOfInterger attributes currently, so If you want to set RangeOfInteger value, maybe you have to write some code like below:

https://github.com/mjhd-devlion/AirPrint.NET/blob/master/IPP/IPP.cs#L76
public struct Attribute
{
	...

	// set raw value to this.Value
	public Attribute(Tag tag, String name, byte[] value)
	{
		this.Tag = tag;
		this.Name = name;
		this.Value = value;
	}

	...
}

https://github.com/mjhd-devlion/AirPrint.NET/blob/master/IPP/IPP.cs#L216
public struct RangeOfInteger
{
	...

	public byte[] ToByte()
	{
		var stream = new MemoryStream();
		var writer = new EndianBinaryWriter(EndianBitConverter.Big, stream);

		// write start and end to EndianBinaryWriter
		writer.Write(this.Start);
		writer.Write(this.End);

		return stream.ToArray();
	}

	...
}

but I have any printers to test this code...sorry.

[ChrisKays]

Hi there,

I would like to know how to set a collection (BegCollection and EndCollection), in your project i put it under as TODO. can you please assist me if you had the chance to finish that part.

Thanks in advance

[mj-hd]

Reading collections

First, the reading a attribute logic should be extracted as a method like ReadAttribute which can be called by parsing collection step recursively.

https://github.com/mj-hd/AirPrint.NET/blob/master/IPP/IPP.cs#L429

1. if tagName BegCollection appears
2. read bytes until endCollection(0x37), and return the bytes

https://github.com/mj-hd/AirPrint.NET/blob/master/IPP/IPP.cs#L131
create new struct constructor to parse the collection bytes into Dictionary, and

1. read next memberAttrName(0x4A) byte and its name, create Dictionary's key and empty List as its value
2. call the ReadAttribute method and store ValueAsObject result to the List until next memberAttrName(0x4A) or endCollection('0x37') appears
3. if memberAttrName(0x4A) appears, go to step 2
4. if endCollection(0x37) appears, return a struct contains the Dictionary

Writing collections

https://github.com/mj-hd/AirPrint.NET/blob/master/IPP/IPP.cs#L88
create new Attribute struct constructor which receives Dictionary<String, List<Attribute>> and returns Attribute contains a byte sequence generated by following step

1. write memberAttrName(0x4A)
2. write key of Dictionary
3. retrieve element of List<Attribute> and call corresponding constructor, write Attribute's value byte sequence
4. write endCollection(0x37)

---

The steps above has not been tested yet, but I hope it will be helpful :)
(and my IPP implementation was inspired by nodejs's IPP, so the code may also be helpful for you.)