314 lines
12 KiB
Go
314 lines
12 KiB
Go
// =============================================================================
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// Auth: alex
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// File: client.go
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// Revn: 10-02-2023 1.0
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// Func: ask server for a message of the day quote
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//
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// TODO: document
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// add more flags?
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// log errors in logfile
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// =============================================================================
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// CHANGE LOG
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// -----------------------------------------------------------------------------
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// 05-11-2022: init
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// 05-17-2022: changed an entry in the response table
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// 08-16-2023: copied from speak.go
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// gutted, rewrote
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// 09-12-2023: added size conversation
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// added -d, -l, and -dest flags
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// commented
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// 09-21-2023: began complete-ass overhaul of handle() system
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// wrote draft of draw()
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// 09-26-2023: made draw return size and reference globals
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// imported check() from soary
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// 09-29-2023: commented handle()
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//*10-02-2023: commented main(), and friends
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//
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// =============================================================================
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package main
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import (
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"io" // io.EOF
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"flag" // BoolVar, StringVar, Parse
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"fmt" // Println
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"math/rand" // NewSource, New, Intn, *rand.Rand
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"net" // ResolveTCPAddr, DialTCP, conn.Write,Read
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"os" // Exit
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"strconv" // Atoi, Itoa
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"strings" // Split
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"time" // Now, UnixNano
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)
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// print errors if they occur, quit
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func check( err error ) {
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var errep string // declare error report string
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switch err { // switch case over error input
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case nil: // if there was no error
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// then there was no error
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errep = "err is nil"
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case io.EOF: // if there was an End Of File error
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errep = "Error: " + err.Error() // document error
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conn.Close() // close connection
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default: // anything besides those are a big deal
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errep = "Fatal: " + err.Error()
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}
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var critical bool // declare critical error flag
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// must be neither nil nor EOF
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critical = err != nil && err != io.EOF
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if critical { // XXX critical print
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// TODO at some point, critical should be logging instead of
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// printing, only verbose should print
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fmt.Println( "check() -> ", errep )
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}
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if critical { // if there was a critical error
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os.Exit( 1 ) // cut and run
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}
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}
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// seed and get a new rng
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func seed() *rand.Rand {
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// use current time to seed random number
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s := rand.NewSource( time.Now().UnixNano() )
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r := rand.New( s ) // create new random number from seed
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return r // return random number
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}
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// get a random number
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func draw() string {
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rn := seed() // get a random seed
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r := rn.Intn( qsize ) // get a random number using seed
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if debug { // XXX debug print
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fmt.Println( "random number: ", r )
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}
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// convert random number to ascii, because converting
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// ints to bytes ( for networking ) and back is obnoxious
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rsz := strconv.Itoa( r )
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if debug { // XXX debug print
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fmt.Println( "converted size var" )
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fmt.Printf( rsz + ": %T\n", rsz )
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}
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return rsz // return rand size
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}
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// get server response and print
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func handle( conn net.Conn ) {
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var buffer [512]byte // create buffer to hold response
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// read n bytes from server into buffer ( byte slice )
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n, err := conn.Read( buffer[:] )
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check( err ) // check for errors
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// split recv'd message over @, separate header from message
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msg := strings.Split( string( buffer[:n] ), "@" )
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var resp string // declare response variable
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switch msg[0] { // switch/case over the header
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// if message is...
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case "sa": // /sa/, size answer
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// convert back half to int, catch error
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size, nerr := strconv.Atoi( msg[1] )
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if nerr == nil { // if there was no error
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qsize = size // set size global to recv'd size
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} else {
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// if int conversion failed, just quit
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// TODO make more robust
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os.Exit( 1 )
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}
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req := draw() // draw a random number
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resp = "qr@" + req // create quote query with rng
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case "ba": // /ba/, bad answer
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// TODO create server-side, and handle client-side
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fmt.Println( "error in " + msg[1] + ": " + msg[2] )
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resp = "te@error" // set transaction end message
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case "qa": // /qa/, quote answer
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fmt.Println( msg[1] ) // whole-ass just print quote
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resp = "te@success" // set transaction end message
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case "la": // /la/, list answer
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// split recv'd message over newline to create quote list
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quotes := strings.Split( msg[1], "\n" )
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for p, v := range quotes { // iterate over quotes
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// print num of quote, followed by that quote
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fmt.Println( p+1, "\t", v )
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}
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resp = "te@success" // set transaction end message
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case "aa": // /aa/, add answer
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// if server says add succeeded
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if msg[1] == "success" {
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fmt.Println( "Add successful" ) // print success
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resp = "te@success" // set transaction end message
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// if server says add failed
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} else if msg[1] == "error" {
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fmt.Println( "Add failed" ) // print fail
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resp = "te@error" // set transaction end message
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// unknown status message
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} else {
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// print unknown status
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fmt.Println( "Unknown status code: " + msg[1] )
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// TODO should this be unknown instead of error?
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resp = "te@error" // set transaction end message
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}
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case "r1": // /r1/, remove ( first transaction )
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// the idea is that if the user doesn't specify which quote to
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// remove, list all quotes and let the user choose the quote
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// to remove. There was probably a way to handle this a little
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// more simply, but this, I feel, has some nuance to it that I
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// actually like
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// redo /la/, list all quotes
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quotes := strings.Split( msg[1], "\n" )
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for p, v := range quotes {
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fmt.Println( p+1, "\t", v )
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}
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// TODO get user input
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case "r2": // /r2/, remove ( second transaction )
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// if server says remove succeeded
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if msg[1] == "success" {
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fmt.Println( "Remove successful" ) // print success
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// list all quotes to validate remove succeeded
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// TODO should /aa/ also make /lr/ before /te/?
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resp = "lr@dumvar" // set transaction end message
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// if server says remove failed
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} else if msg[1] == "error" {
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fmt.Println( "Remove failed" ) // print failure
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resp = "te@error" // set transaction end message
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// if unknown status message
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} else {
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// print unknown status
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fmt.Println( "Unknown error code: " + msg[1] )
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// TODO should this be unknown instead of error?
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resp = "te@error" // set transaction end message
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}
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case "br": // /br/, bad request
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// client has asked for something nonsensical
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// TODO write out to file
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fmt.Println( "Client sent a bad request" )
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resp = "te@error" // set transaction end message
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default: // something undefined entirely
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// TODO write out to file
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fmt.Println( "Message header not recognized" )
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fmt.Println( msg )
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conn.Close() // TODO how important is this line
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return // dead return, essentially lets program quit
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}
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if debug { // XXX debug print
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fmt.Print( "raw read: " + strconv.Itoa( n ) + " bytes " )
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fmt.Println( buffer[:n] )
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}
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// send formulated response back to server
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_, err = conn.Write( []byte( resp ) )
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check( err ) // make sure write worked
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handle( conn ) // call handle again
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}
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// globals
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var qsize int // keep track of num of quotes
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var conn net.Conn // keep track of connection
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// global flag variables
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var debug bool // debug prints useful information
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var add bool // add new quotes to quote file ( on server )
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var remove bool // remove quotes from quote file ( on server )
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var list bool // request entire quote file from server
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var dest string // provide a new destination ip and port
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func main() {
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// define flags
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flag.BoolVar( &debug, "d", false, "print debug info" )
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flag.BoolVar( &add, "a", false, "add quote to list" )
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flag.BoolVar( &remove, "r", false, "remove quote from list" )
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flag.BoolVar( &list, "l", false, "print quote list" )
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flag.StringVar( &dest, "ip", ":1300", "ip:port of server" )
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flag.Parse() // process flags
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if debug { // XXX debug print
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fmt.Println( "ip:port = ", dest )
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}
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service := dest // declare server ip:port
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// create address object
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addr, err := net.ResolveTCPAddr( "tcp", service )
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check( err ) // check for errors
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// make connection with object
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conn, err = net.DialTCP( "tcp", nil, addr )
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check( err ) // check for errors
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// block for all flags
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var command string
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switch { // empty switch statement is basically an if
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case list: // if list flag is active
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command = "lr@dumvar" // list request
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// TODO come up with a useful argument, instead of dumvar
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case add: // if add flag is active
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// if arguments were specified
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if len( flag.Args() ) != 0 {
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command = "ar@" // preface command w/ add request
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// need to concat flag.args
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for _, v := range flag.Args() {
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// add the string and a space to command
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command = command + v + " "
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}
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// remove the trailing space
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command = command[:len( command ) - 1]
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} else { // if no arguments were specified
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// print that you need args and bail
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fmt.Println( "/a/ flag must be used with an arugment" )
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os.Exit( 1 )
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}
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case remove: // if remove flag is active
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// if arguments were specified
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if len( flag.Args() ) >= 0 {
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// argument is supposed to the number of the quote to
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// be removed, get first arg
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// cast to int just to make sure it's a valid number
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// assuming the user knows what they're doing
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_, rerr := strconv.Atoi( flag.Args()[0] )
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// if there was an error, just pretend there's no args
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if rerr != nil {
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command = "r1@dumvar" // remove request 1
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// TODO come up w/ useful argument, replace dumvar
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} else {
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// if user knows the number, take care of it
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// arg[0] is a string, so concat is cool
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// jump right into remove request 2
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command = "r2@" + flag.Args()[0]
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}
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} else { // if no argument was specified for remove
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// jump right into remove request 1
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command = "r1@dumvar"
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}
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default: // if no flag was specified
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// begin transaction for quote request
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command = "sr@please" // size request
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}
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// write command to server, beginning transaction
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_, err = conn.Write( []byte( command ) )
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check( err ) // make sure write worked
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handle( conn ) // handle response
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// TODO stack trace when handle returns, should probably be
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// updated
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conn.Close() // close connection when finished
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os.Exit( 0 ) // exit
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}
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