qbeon/webwire-go

package message

import (
    "fmt"
    "io"
)

// WriteMsgReplyError writes an error reply message to the given writer
// closing it eventually
func WriteMsgReplyError(
    writer io.WriteCloser,
    requestIdent []byte,
    code,
    message []byte,
    safeMode bool,
) error {
    if safeMode {
        // Validate input
        if len(code) < 1 {
            initialErr := fmt.Errorf(
                "missing error code while creating a new error reply message",
            )
            if err := writer.Close(); err != nil {
                return fmt.Errorf("%s: %s", initialErr, err)
            }
            return initialErr
        } else if len(code) > 255 {
            initialErr := fmt.Errorf(
                "invalid error code while creating a new error reply message,"+
                    "too long (%d)",
                len(code),
            )
            if err := writer.Close(); err != nil {
                return fmt.Errorf("%s: %s", initialErr, err)
            }
            return initialErr
        }
        // Determine total message length
        // messageSize := 10 + len(code) + len(message)
        // if len(buf) < messageSize {
        //    if closeErr := writer.Close(); closeErr != nil {
        //     return fmt.Errorf("%s: %s", err, closeErr)
        // }
        //     return 0, errors.New(
        //         "message buffer too small to fit an error reply message",
        //     )
        // }
        for _, char := range code {
            if char < 32 || char > 126 {
                initialErr := fmt.Errorf(
                    "unsupported character in reply error - error code: %s",
                    string(char),
                )
                if closeErr := writer.Close(); closeErr != nil {
                    return fmt.Errorf("%s: %s", initialErr, closeErr)
                }
                return initialErr
            }
        }
    }

    // Write message type flag
    if _, err := writer.Write(msgTypeReplyError); err != nil {
        if closeErr := writer.Close(); closeErr != nil {
            return fmt.Errorf("%s: %s", err, closeErr)
        }
        return err
    }

    // Write request identifier
    if _, err := writer.Write(requestIdent); err != nil {
        if closeErr := writer.Close(); closeErr != nil {
            return fmt.Errorf("%s: %s", err, closeErr)
        }
        return err
    }

    // Write code length flag
    if _, err := writer.Write(
        msgNameLenBytes[len(code) : len(code)+1],
    ); err != nil {
        if closeErr := writer.Close(); closeErr != nil {
            return fmt.Errorf("%s: %s", err, closeErr)
        }
        return err
    }

    // Write error code
    if _, err := writer.Write(code); err != nil {
        if closeErr := writer.Close(); closeErr != nil {
            return fmt.Errorf("%s: %s", err, closeErr)
        }
        return err
    }

    // Write error message
    if _, err := writer.Write(message); err != nil {
        if closeErr := writer.Close(); closeErr != nil {
            return fmt.Errorf("%s: %s", err, closeErr)
        }
        return err
    }

    return writer.Close()
}