A working proxy exists.

packages/ipp/request.go

@@ -38,7 +38,7 @@ type AddValuer interface {
 }
 
 type Request struct {
-	a      *attributes
+	a      *Attributes
 	header ippMessageHeader
 }
 
@@ -47,7 +47,7 @@ func NewRequest(op OperationID, requestID uint32) *Request {
 	r.header.operationID = op
 	r.header.requestID = requestID
 	r.header.versionNumber = 0x0200
-	r.a = new(attributes)
+	r.a = new(Attributes)
 	return r
 }
 
@@ -58,7 +58,6 @@ func (r Request) String() string {
 func (r *Request) UnMarshal(body io.Reader) {
 	buffbody := bufio.NewReader(body)
 	r.header.unmarshal(buffbody)
-	//log.Printf("Header %v", r.header)
 	r.a = UnMarshalAttributes(buffbody)
 }
 
@@ -76,9 +75,25 @@ func (r *Request) GetAttribute(name string) Attribute {
 			return a
 		}
 	}
+	for _, a := range r.a.job {
+		if a.Name() == name {
+			return a
+		}
+	}
+	for _, a := range r.a.printer {
+		if a.Name() == name {
+			return a
+		}
+	}
+	for _, a := range r.a.unsupported {
+		if a.Name() == name {
+			return a
+		}
+	}
 	return nil
 }
 
+// Marshal converts the request object to a ipp request
 func (r *Request) Marshal() []byte {
 
 	var buf bytes.Buffer
@@ -105,14 +120,29 @@ func (r *Request) Marshal() []byte {
 	return buf.Bytes()
 }
 
-func (r *Request) AddPrinterAttribute(a Attribute) {
-	r.a.addAttribute(printerAttributes, a)
+// AddPrinterAttribute adds a printer attribute to the request object
+func (r *Request) AddPrinterAttribute(a Attribute) error {
+	if a != nil {
+		r.a.addAttribute(printerAttributes, a)
+		return nil
+	}
+	return ErrNilAttribute
 }
 
-func (r *Request) AddOperatonAttribute(a Attribute) {
-	r.a.addAttribute(operationAttributes, a)
+// AddOperatonAttribute adds a operation attribute to the request object
+func (r *Request) AddOperatonAttribute(a Attribute) error {
+	if a != nil {
+		r.a.addAttribute(operationAttributes, a)
+		return nil
+	}
+	return ErrNilAttribute
 }
 
-func (r *Request) AddJobAttribute(a Attribute) {
-	r.a.addAttribute(jobAttributes, a)
+// AddJobAttribute adds a job attribute to the request object
+func (r *Request) AddJobAttribute(a Attribute) error {
+	if a != nil {
+		r.a.addAttribute(jobAttributes, a)
+		return nil
+	}
+	return ErrNilAttribute
 }