79 lines
1.6 KiB
Go
79 lines
1.6 KiB
Go
package api
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import (
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"encoding/binary"
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"encoding/json"
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"fmt"
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"net"
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)
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var (
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printer_server_IP = net.ParseIP("127.0.0.1")
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printer_server_port = 4444
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)
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/**
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* All messages from and to the API must have the first 4 bytes set to represent
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* the length of the message, followed by the message itself
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*/
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func sendJSONToServer[T JSONCommand](socket *net.TCPConn, json_command T) (*net.TCPConn, error) {
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json_data, err := json.Marshal(json_command)
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if err != nil {
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return nil, err
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}
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// in case a socket doesn't already exist create a new one
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if socket == nil {
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socket, err = net.DialTCP("tcp4", nil, &net.TCPAddr{printer_server_IP, printer_server_port, ""})
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}
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if err != nil {
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return nil, err
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}
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// the first 4 bytes must be the length of the message
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to_send := make([]byte, 4)
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binary.LittleEndian.PutUint32(to_send, uint32(len(json_data)))
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to_send = append(to_send, json_data...)
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socket.Write([]byte(to_send))
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return socket, nil
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}
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func receiveJSONFromServer[T JSONReceived](socket *net.TCPConn, json_received *T) (*net.TCPConn, error) {
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var err error
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// in case a socket doesn't already exist create a new one
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if socket == nil {
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fmt.Println("nil")
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socket, err = net.DialTCP("tcp4", nil, &net.TCPAddr{printer_server_IP, printer_server_port, ""})
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}
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if err != nil {
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return nil, err
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}
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// the first 4 bytes are the length of the message
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b := make([]byte, 4)
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_, err = socket.Read(b[0:])
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if err != nil {
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return nil, err
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}
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body_length := binary.LittleEndian.Uint32(b)
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body := make([]byte, body_length)
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_, err = socket.Read(body[0:])
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err = json.Unmarshal(body, json_received)
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if err != nil {
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return nil, err
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}
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return socket, nil
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}
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