added README and fixed charset bug

README.md

@@ -0,0 +1,42 @@
+# ipp-printjob-kotlin
+
+A minimal ipp client implementation for jvm written in kotlin.
+
+
+### Build
+
+In order to build the software you need an installed JDK.
+
+    ./gradlew
+
+When the build has finished you can find `printjob.jar` in `build/libs`
+
+### Distribution
+
+If you don't want to build the software [binary releases](https://github.com/gmuth/ipp-printjob-kotlin/releases) are provided.
+
+### Usage
+
+The tool takes two arguments: *printer-uri* and *file-name*. \
+The url scheme `ipp://` is not supported - use `http://` instead. \
+If you don't know the printer uri try `ippfind`. 
+
+    java -jar printjob.jar http://colorjet:631/ipp/printer A4-blank.pdf
+
+    send ipp request to http://colorjet:631/ipp/printer
+    ipp response status: 0000
+    group 01
+       attributes-charset (47) = utf-8
+       attributes-natural-language (48) = en
+    group 02
+       job-uri (45) = ipp://colorjet:631/jobs/352
+       job-id (21) = 352
+       job-state (23) = 3
+       job-state-reasons (44) = none
+    group 03
+
+### Document Format
+
+The operation attributes group does not include a value for `document-format`.
+This should be equivalent to `application/octet-stream` indicating the printer has to auto sense the document format.
+You have to make sure the printer supports the document format you send - PDF is usually a good option. 

demo/.gitignore

@@ -0,0 +1 @@
+!printjob.jar

demo/go

@@ -1 +1 @@
-java -jar ../build/libs/printjob.jar http://localhost:8632/printers/laser A4-blank.pdf
+java -jar printjob.jar http://localhost:8632/printers/laser A4-blank.pdf

src/main/kotlin/ipp/printjob.kt

@@ -1,9 +1,9 @@
 package ipp
+
 // --------------------
 // Author: Gerhard Muth
 // Date  : 14.3.2020
 // --------------------
-
 import java.io.*
 import java.net.HttpURLConnection
 import java.net.URI
@@ -30,13 +30,13 @@ fun printJob(uri: URI, documentInputStream: InputStream) {
             write(value.toByteArray(charset))
         }
         writeShort(0x0200) // ipp version
-        writeShort(0x0002) // OPERATION Print-Job
+        writeShort(0x0002) // print job operation
         writeInt(0x002A) // request id
-        writeByte(0x01) // GROUP operation-attributes-tag
-        writeAttribute(0x47, "attributes-charset", "$charset")    // ATTR charset attributes-charset utf-8
-        writeAttribute(0x48, "attributes-natural-language", "en") // ATTR language attributes-natural-language en
-        writeAttribute(0x45, "printer-uri", "$uri")               // ATTR uri printer-uri $uri
-        writeByte(0x03) // GROUP end-tag
+        writeByte(0x01) // operation group tag
+        writeAttribute(0x47, "attributes-charset", charset.name().toLowerCase())
+        writeAttribute(0x48, "attributes-natural-language", "en")
+        writeAttribute(0x45, "printer-uri", "$uri")
+        writeByte(0x03) // end tag
         close()
         byteArrayOutputStream.close()
         byteArrayOutputStream.toByteArray()
@@ -46,7 +46,7 @@ fun printJob(uri: URI, documentInputStream: InputStream) {
     println("send ipp request to $uri")
     val ippResponse = with(uri.toURL().openConnection() as HttpURLConnection) {
         val ippContentType = "application/ipp"
-        setConnectTimeout(3)
+        setConnectTimeout(3000)
         setDoOutput(true)
         setRequestProperty("Content-Type", ippContentType)
         val ippRequestInputStream = ippRequest.inputStream()