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/* Go IPP - IPP core protocol implementation in pure Go
/*
* Copyright (C) 2020 and up by Alexander Pevzner (pzz@apevzner.com)
* See LICENSE for license terms and conditions
*
* Package documentation
*/
/*
Package goipp implements IPP core protocol, as defined by RFC 8010
It doesn't implement high-level operations, such as "print a document",
"cancel print job" and so on. It's scope is limited to proper generation
and parsing of IPP requests and responses.
IPP protocol uses the following simple model:
1. Send a request
2. Receive a response
Request and response both has a similar format, represented here
by type Message, with the only difference, that Code field of
that Message is the Operation code in request and Status code
in response. So most of operations are common for request and
response messages
# Example (Get-Printer-Attributes):
package main
import (
"bytes"
"net/http"
"os"
"github.com/OpenPrinting/goipp"
)
const uri = "http://192.168.1.102:631"
// Build IPP OpGetPrinterAttributes request
func makeRequest() ([]byte, error) {
m := goipp.NewRequest(goipp.DefaultVersion, goipp.OpGetPrinterAttributes, 1)
m.Operation.Add(goipp.MakeAttribute("attributes-charset",
goipp.TagCharset, goipp.String("utf-8")))
m.Operation.Add(goipp.MakeAttribute("attributes-natural-language",
goipp.TagLanguage, goipp.String("en-US")))
m.Operation.Add(goipp.MakeAttribute("printer-uri",
goipp.TagURI, goipp.String(uri)))
m.Operation.Add(goipp.MakeAttribute("requested-attributes",
goipp.TagKeyword, goipp.String("all")))
return m.EncodeBytes()
}
// Check that there is no error
func check(err error) {
if err != nil {
panic(err)
}
}
func main() {
request, err := makeRequest()
check(err)
resp, err := http.Post(uri, goipp.ContentType, bytes.NewBuffer(request))
check(err)
var respMsg goipp.Message
err = respMsg.Decode(resp.Body)
check(err)
respMsg.Print(os.Stdout, false)
}
# Example (Print PDF file):
package main
import (
"bytes"
"errors"
"fmt"
"io"
"net/http"
"os"
"github.com/OpenPrinting/goipp"
)
const (
PrinterURL = "http://192.168.1.102:631/ipp/print"
TestPage = "onepage-a4.pdf"
)
type T int
// checkErr checks for an error. If err != nil, it prints error
// message and exits
func checkErr(err error, format string, args ...interface{}) {
if err != nil {
msg := fmt.Sprintf(format, args...)
fmt.Fprintf(os.Stderr, "%s: %s\n", msg, err)
os.Exit(1)
}
}
// ExamplePrintPDF demo
func main() {
// Build and encode IPP request
req := goipp.NewRequest(goipp.DefaultVersion, goipp.OpPrintJob, 1)
req.Operation.Add(goipp.MakeAttribute("attributes-charset",
goipp.TagCharset, goipp.String("utf-8")))
req.Operation.Add(goipp.MakeAttribute("attributes-natural-language",
goipp.TagLanguage, goipp.String("en-US")))
req.Operation.Add(goipp.MakeAttribute("printer-uri",
goipp.TagURI, goipp.String(PrinterURL)))
req.Operation.Add(goipp.MakeAttribute("requesting-user-name",
goipp.TagName, goipp.String("John Doe")))
req.Operation.Add(goipp.MakeAttribute("job-name",
goipp.TagName, goipp.String("job name")))
req.Operation.Add(goipp.MakeAttribute("document-format",
goipp.TagMimeType, goipp.String("application/pdf")))
payload, err := req.EncodeBytes()
checkErr(err, "IPP encode")
// Open document file
file, err := os.Open(TestPage)
checkErr(err, "Open document file")
defer file.Close()
// Build HTTP request
body := io.MultiReader(bytes.NewBuffer(payload), file)
httpReq, err := http.NewRequest(http.MethodPost, PrinterURL, body)
checkErr(err, "HTTP")
httpReq.Header.Set("content-type", goipp.ContentType)
httpReq.Header.Set("accept", goipp.ContentType)
httpReq.Header.Set("accept-encoding", "gzip, deflate, identity")
// Execute HTTP request
httpRsp, err := http.DefaultClient.Do(httpReq)
if httpRsp != nil {
defer httpRsp.Body.Close()
}
checkErr(err, "HTTP")
if httpRsp.StatusCode/100 != 2 {
checkErr(errors.New(httpRsp.Status), "HTTP")
}
// Decode IPP response
rsp := &goipp.Message{}
err = rsp.Decode(httpRsp.Body)
checkErr(err, "IPP decode")
if goipp.Status(rsp.Code) != goipp.StatusOk {
err = errors.New(goipp.Status(rsp.Code).String())
checkErr(err, "IPP")
}
}
*/
package goipp
|
