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package goagi |
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import ( |
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"bufio" |
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"strings" |
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) |
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// ErrAGI goagi error |
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var ErrAGI = newError("AGI session") |
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// Reader interface for AGI object. Can be net.Conn, os.File or crafted |
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type Reader interface { |
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Read(b []byte) (int, error) |
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} |
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// Writer interface for AGI object. Can be net.Conn, os.File or crafted |
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type Writer interface { |
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Write(b []byte) (int, error) |
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} |
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// Debugger for AGI instance. Any interface that provides Printf method. |
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// It should be used only for debugging as it give lots of output. |
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type Debugger interface { |
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Printf(format string, v ...interface{}) |
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} |
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// AGI object |
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type AGI struct { |
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env map[string]string |
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arg []string |
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reader Reader |
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writer Writer |
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isHUP bool |
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debugger Debugger |
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} |
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const ( |
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codeUnknown int = 0 |
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codeEarly = 100 |
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codeSucc = 200 |
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codeE503 = 503 |
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codeE510 = 510 |
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codeE511 = 511 |
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codeE520 = 520 |
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) |
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var codeMap = map[string]int{ |
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"100 ": codeEarly, |
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"200 ": codeSucc, |
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"503 ": codeE503, |
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"510 ": codeE510, |
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"511 ": codeE511, |
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"520 ": codeE520, |
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} |
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/* |
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New creates and returns AGI object. |
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Can be used to create agi and fastagi sessions. |
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Parameters: |
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- Reader that implements Read method |
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- Writer that implements Write method |
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- Debugger that allows to deep library debugging. Nil for production. |
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*/ |
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func New(r Reader, w Writer, dbg Debugger) (*AGI, error) { |
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agi := &AGI{ |
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reader: r, |
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writer: w, |
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debugger: dbg, |
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} |
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agi.dbg("[>] New AGI") |
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sessData, err := agi.sessionInit() |
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if err != nil { |
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return nil, ErrAGI.Msg("Failed to read setup: %s", err) |
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} |
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agi.sessionSetup(sessData) |
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return agi, nil |
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} |
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// Env returns AGI environment variable by key |
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func (agi *AGI) Env(key string) string { |
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agi.dbg("[>] Env for %q", key) |
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val, ok := agi.env[key] |
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if ok { |
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return val |
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} |
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return "" |
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} |
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// EnvArgs returns list of environment arguments |
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func (agi *AGI) EnvArgs() []string { |
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agi.dbg("[>] EnvArgs") |
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return agi.arg |
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} |
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// IsHungup returns true if AGI channel recieved HANGUP signal |
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func (agi *AGI) IsHungup() bool { |
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return agi.isHUP |
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} |
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func (agi *AGI) sessionInit() ([]string, error) { |
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agi.dbg("[>] sessionInit") |
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buf := bufio.NewReader(agi.reader) |
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data := make([]string, 0) |
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for { |
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line, err := buf.ReadString('\n') |
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if err != nil { |
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return nil, err |
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} |
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if line == "\n" { |
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break |
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} |
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agi.dbg(" [v] read line: %q", line) |
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data = append(data, line[:len(line)-1]) |
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} |
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return data, nil |
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} |
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func (agi *AGI) dbg(pattern string, vargs ...interface{}) { |
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if agi.debugger != nil { |
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pattern += "\n" |
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agi.debugger.Printf(pattern, vargs...) |
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} |
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} |
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// low level response from device and response as string, matched response |
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// code, true if channel reported as hangup and error. |
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func (agi *AGI) read() (resp string, code int, err error) { |
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agi.dbg("[>] readResponse") |
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buf := bufio.NewReader(agi.reader) |
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var builder strings.Builder |
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moreInputExpected := false |
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for { |
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line, fail := buf.ReadString('\n') |
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if fail != nil { |
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err = fail |
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return |
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} |
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agi.dbg(" [v] got line: %q", line) |
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builder.WriteString(line) |
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resp = builder.String() |
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if codeMatch, ok := matchCode(line); ok { |
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code = codeMatch |
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return |
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} |
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if matchPrefix(line, "520-") { |
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moreInputExpected = true |
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} |
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if matchPrefix(line, "HANGUP") { |
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agi.isHUP = true |
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builder.Reset() |
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continue |
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} |
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if !moreInputExpected { |
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err = ErrAGI.Msg("Invalid input while reading response: %q", resp) |
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return |
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} |
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} |
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} |
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func matchPrefix(line, pattern string) bool { |
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if len(line) < len(pattern) { |
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return false |
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} |
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return line[:len(pattern)] == pattern |
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} |
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func matchCode(data string) (int, bool) { |
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if len(data) < 4 { |
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return 0, false |
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} |
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if codeMatch, ok := codeMap[data[:4]]; ok { |
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return codeMatch, true |
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} |
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return 0, false |
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} |
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func (agi *AGI) write(command []byte) error { |
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agi.dbg("[>] readResponse") |
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agi.dbg(" [v] writing command: %q", string(command)) |
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_, err := agi.writer.Write(command) |
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if err != nil { |
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return err |
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} |
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agi.dbg(" [v] write successfully done") |
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return nil |
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} |
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// write command, read and parse response |
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func (agi *AGI) execute(cmd string) (Response, error) { |
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agi.dbg("[>] execute cmd: %q", cmd) |
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if err := agi.write([]byte(cmd)); err != nil { |
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return nil, err |
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} |
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resp, code, err := agi.read() |
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if err != nil { |
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return nil, err |
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} |
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return agi.parseResponse(resp, code) |
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} |
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