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// Copyright (C) 2019 LEAP
//
// This program is free software: you can redistribute it and/or modify
// it under the terms of the GNU General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program. If not, see <http://www.gnu.org/licenses/>.
package sip2
import (
"errors"
"log"
"strconv"
"strings"
)
const (
yes string = "Y"
no string = "N"
trueVal string = "1"
falseVal string = "0"
okVal string = "ok"
language string = "language"
patronStatus string = "patron status"
onlineStatus string = "on-line status"
checkinOk string = "checkin ok"
checkoutOk string = "checkout ok"
renewalPolicy string = "acs renewal policy"
statusUpdate string = "status update ok"
offlineOK string = "offline ok"
timeoutPeriod string = "timeout period"
retriesAllowed string = "retries allowed"
dateTimeSync string = "date/time sync"
date string = "transaction date"
patronIdentifier string = "patron identifier"
patronPassword string = "patron password"
protocolVersion string = "protocol version"
personalName string = "personal name"
screenMessage string = "screen message"
institutionID string = "institution id"
validPatron string = "valid patron"
validPatronPassword string = "valid patron password"
loginResponse string = "Login Response"
ascStatus string = "ASC Status"
patronStatusResponse string = "Patron Status Response"
)
type fixedFieldSpec struct {
length int
label string
}
type fixedField struct {
spec fixedFieldSpec
value string
}
type variableFieldSpec struct {
id string
label string
}
type variableField struct {
spec variableFieldSpec
value string
}
type messageSpec struct {
id int
label string
fields []fixedFieldSpec
}
func toBool(val string) (bool, error) {
var ret bool
switch val {
case trueVal:
ret = true
case falseVal:
ret = false
case yes:
ret = true
case no:
ret = false
default:
return false, errors.New("cannot parse value")
}
return ret, nil
}
type message struct {
fields []variableField
fixedFields []fixedField
msgTxt string
}
func (m *message) getFieldValue(field string) (string, bool) {
for _, v := range m.fields {
if v.spec.label == field {
return v.value, true
}
}
return "", false
}
func (m *message) getFixedFieldValue(field string) (string, bool) {
for _, v := range m.fixedFields {
if v.spec.label == field {
return v.value, true
}
}
return "", false
}
func (m *message) getValueByCode(code string) (string, bool) {
for _, v := range m.fields {
if v.spec.id == code {
return v.value, true
}
}
return "", false
}
type Parser struct {
msgByCodeMap map[int]messageSpec
variableFieldByCodeMap map[string]variableFieldSpec
}
func getParser() *Parser {
languageSpec := fixedFieldSpec{3, language}
patronStatusSpec := fixedFieldSpec{14, patronStatus}
dateSpec := fixedFieldSpec{18, date}
okSpec := fixedFieldSpec{1, okVal}
onlineStatusSpec := fixedFieldSpec{1, onlineStatus}
checkinOkSpec := fixedFieldSpec{1, checkinOk}
checkoutOkSpec := fixedFieldSpec{1, checkoutOk}
renewalSpec := fixedFieldSpec{1, renewalPolicy}
stUpdateSpec := fixedFieldSpec{1, statusUpdate}
offlineOkSpec := fixedFieldSpec{1, offlineOK}
timeoutSpec := fixedFieldSpec{3, timeoutPeriod}
retriesSpec := fixedFieldSpec{3, retriesAllowed}
dateTimeSyncSpec := fixedFieldSpec{18, dateTimeSync}
protoSpec := fixedFieldSpec{4, protocolVersion}
msgByCodeMap := map[int]messageSpec{
24: messageSpec{24, patronStatusResponse, []fixedFieldSpec{patronStatusSpec, languageSpec, dateSpec}},
94: messageSpec{94, loginResponse, []fixedFieldSpec{okSpec}},
98: messageSpec{98, ascStatus, []fixedFieldSpec{onlineStatusSpec, checkinOkSpec, checkoutOkSpec, renewalSpec, stUpdateSpec, offlineOkSpec, timeoutSpec, retriesSpec, dateTimeSyncSpec, protoSpec}},
}
variableFieldByCodeMap := map[string]variableFieldSpec{
"AA": variableFieldSpec{"AA", patronIdentifier},
"AD": variableFieldSpec{"AD", patronPassword},
"AE": variableFieldSpec{"AE", personalName},
"AF": variableFieldSpec{"AF", screenMessage},
"AO": variableFieldSpec{"AO", institutionID},
"BL": variableFieldSpec{"BL", validPatron},
"CQ": variableFieldSpec{"CQ", validPatronPassword},
}
return &Parser{msgByCodeMap, variableFieldByCodeMap}
}
func (p *Parser) getMessageSpecByCode(code int) messageSpec {
return p.msgByCodeMap[code]
}
func (p *Parser) getVariableFieldByCode(code string) variableFieldSpec {
return p.variableFieldByCodeMap[code]
}
func (p *Parser) getFixedFieldValue(msg *message, field string) (string, bool) {
for _, v := range msg.fixedFields {
if v.spec.label == field {
return v.value, true
}
}
return "", false
}
func (p *Parser) parseMessage(msg string) (*message, error) {
if len(msg) == 0 {
return &message{}, errors.New("empty message")
}
if len(msg) < (2 + len(telnetTerminator)) {
return &message{}, errors.New("parseMessage: message too short")
}
txt := msg[:len(msg)-len(telnetTerminator)]
code, err := strconv.Atoi(txt[:2])
if nil != err {
log.Printf("Error parsing integer: %s\n", txt[:2])
return &message{}, errors.New("parseMessage: error parsing integer")
}
spec := p.getMessageSpecByCode(code)
txt = txt[2:]
message := new(message)
for _, sp := range spec.fields {
value := txt[:sp.length]
txt = txt[sp.length:]
message.fixedFields = append(message.fixedFields, fixedField{sp, value})
}
if len(txt) == 0 {
return message, nil
}
for _, part := range strings.Split(txt, "|") {
if len(part) > 0 {
partSpec := p.getVariableFieldByCode(part[:2])
value := part[2:]
message.fields = append(message.fields, variableField{partSpec, value})
}
}
return message, nil
}
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