wrote up to level 3 piece-wise file transmission

dev/seq/Makefile

@@ -0,0 +1,7 @@
+all: client server
+
+client:
+	go build -o ekho client.go
+
+server:
+	go build -o motd server.go

dev/seq/client.go

@@ -0,0 +1,321 @@
+// =============================================================================
+// Auth: alex
+// File: client.go
+// Revn: 10-05-2023  2.0
+// Func: ask server for a message of the day quote
+//
+// TODO: document
+//       expand on /ba/ failures
+//       add more flags?
+//       log errors in logfile
+// =============================================================================
+// CHANGE LOG
+// -----------------------------------------------------------------------------
+// 05-11-2022: init
+// 05-17-2022: changed an entry in the response table
+// 08-16-2023: copied from speak.go
+//             gutted, rewrote
+// 09-12-2023: added size conversation
+//             added -d, -l, and -dest flags
+//             commented
+// 09-21-2023: began complete-ass overhaul of handle() system
+//             wrote draft of draw()
+// 09-26-2023: made draw return size and reference globals
+//             imported check() from soary
+// 09-29-2023: commented handle()
+//*10-02-2023: commented main(), and friends
+//*10-05-2023: /remove/ works
+//             removed -d flag
+//             commented
+//
+// =============================================================================
+
+package main
+
+import ( 
+    "io"        // io.EOF
+    "flag"      // BoolVar, StringVar, Parse
+    "fmt"       // Println
+    "math/rand" // NewSource, New, Intn, *rand.Rand
+    "net"       // ResolveTCPAddr, DialTCP, conn.Write,Read
+    "os"        // Exit
+    "strconv"   // Atoi, Itoa
+    "strings"   // Split
+    "time"      // Now, UnixNano
+)
+
+
+// print errors if they occur, quit
+func check( err error ) {
+
+    var errep string    // declare error report string
+    switch err {        // switch case over error input
+        case nil:       // if there was no error
+            // then there was no error
+            errep = "err is nil"
+        case io.EOF:    // if there was an End Of File error
+            errep = "Error: " + err.Error()     // document error
+            conn.Close()    // close connection
+        default:    // anything besides those are a big deal
+            errep = "Fatal: " + err.Error()
+    }
+
+    var critical bool   // declare critical error flag
+    // must be neither nil nor EOF
+    critical = err != nil && err != io.EOF
+    if critical {   // XXX critical print
+        // TODO at some point, critical should be logging instead of
+        // printing, only verbose should print
+        fmt.Println( "check() -> ", errep )
+    }
+    
+    if critical {       // if there was a critical error
+        os.Exit( 1 )    // cut and run
+    }
+}
+
+
+// get user input
+func in( prompt string ) string {
+    fmt.Print( prompt )     // print user prompt
+    var input string        // declare var to hold user input
+    fmt.Scanln( &input )    // get user input
+    // try to convert to an int, discard results
+    _, err := strconv.Atoi( input )
+    // if there was an error, user didn't input an int
+    if err != nil {
+        // warn user against this
+        fmt.Println( "Input must be a number" )
+        input = in( prompt )    // try to get user input again
+        // this, like handle() calling handle(), seems like a super
+        // bad idea, stack-wise...
+    }
+    // once user has properly inputted a number, return string of num
+    return input
+}
+
+
+// seed and get a new rng
+func seed() *rand.Rand {
+    // use current time to seed random number
+    s := rand.NewSource( time.Now().UnixNano() )
+    r := rand.New( s )  // create new random number from seed
+    return r            // return random number
+}
+
+
+// get a random number
+func draw() string {
+    rn := seed()            // get a random seed
+    r := rn.Intn( qsize )   // get a random number using seed
+    // convert random number to ascii, because converting
+    // ints to bytes ( for networking ) and back is obnoxious
+    rsz := strconv.Itoa( r )
+    return rsz      // return rand size
+}
+
+
+// get server response and print
+func handle( conn net.Conn ) {
+
+    var buffer [512]byte    // create buffer to hold response
+    // read n bytes from server into buffer ( byte slice )
+    n, err := conn.Read( buffer[:] )
+    check( err )    // check for errors
+
+    // split recv'd message over @, separate header from message
+    msg := strings.Split( string( buffer[:n] ), "@" )
+
+    var resp string     // declare response variable
+    switch msg[0] {     // switch/case over the header
+        // if message is...
+        case "sa":      // /sa/, size answer
+            // convert back half to int, catch error
+            size, nerr := strconv.Atoi( msg[1] )
+            if nerr == nil {    // if there was no error
+                qsize = size    // set size global to recv'd size
+            } else {
+                // if int conversion failed, just quit
+                // TODO make more robust
+                os.Exit( 1 )
+            }
+            req := draw()           // draw a random number
+            resp = "qr@" + req      // create quote query with rng
+        case "ba":      // /ba/, bad answer
+            // TODO create server-side, and handle client-side
+            fmt.Println( "error in " + msg[1] + ": " + msg[2] )
+            resp = "te@error"   // set transaction end message
+        case "qa":      // /qa/, quote answer
+            fmt.Println( msg[1] )   // whole-ass just print quote
+            resp = "te@success"     // set transaction end message
+        case "la":      // /la/, list answer
+            // split recv'd message over newline to create quote list
+            quotes := strings.Split( msg[1], "\n" )
+            for p, v := range quotes {      // iterate over quotes
+                // print num of quote, followed by that quote
+                fmt.Println( p + 1, "\t", v )
+            }
+            resp = "te@success"     // set transaction end message
+        case "aa":      // /aa/, add answer
+            // if server says add succeeded
+            if msg[1] == "success" {
+                fmt.Println( "Add successful" )     // print success
+                resp = "te@success" // set transaction end message
+            // if server says add failed
+            } else if msg[1] == "error" {
+                fmt.Println( "Add failed" )     // print fail
+                resp = "te@error"   // set transaction end message
+            // unknown status message
+            } else {
+                // print unknown status
+                fmt.Println( "Unknown status code: " + msg[1] )
+                // TODO should this be unknown instead of error?
+                resp = "te@error"   // set transaction end message
+            }
+        case "r1":      // /r1/, remove ( first transaction )
+        // the idea is that if the user doesn't specify which quote to
+        // remove, list all quotes and let the user choose the quote
+        // to remove. There was probably a way to handle this a little
+        // more simply, but this, I feel, has some nuance to it that I
+        // actually like
+            // redo /la/, list all quotes
+            // split recv'd message over newline to create quote list
+            quotes := strings.Split( msg[1], "\n" )
+            for p, v := range quotes {      // iterate over quotes
+                // print num of quote, followed by that quote
+                fmt.Println( p + 1, "\t", v )
+            }
+            // ask user which quote to remove
+            resp = "r2@" + in( "\n-> " )
+        case "r2":      // /r2/, remove ( second transaction )
+            // if server says remove succeeded
+            if msg[1] == "success" {
+                fmt.Println( "Remove successful\n" )    // success
+                // list all quotes to validate remove succeeded
+                // TODO should /aa/ also make /lr/ before /te/?
+                resp = "lr@dumvar"  // set transaction end message
+            // if server says remove failed
+            } else if msg[1] == "error" {
+                fmt.Println( "Remove failed" )      // print failure
+                resp = "te@error"   // set transaction end message
+            // if unknown status message
+            } else {
+                // print unknown status
+                fmt.Println( "Unknown error code: " + msg[1] )
+                // TODO should this be unknown instead of error?
+                resp = "te@error"   // set transaction end message
+            }
+        case "br":      // /br/, bad request
+        // client has asked for something nonsensical
+            // TODO write out to file
+            fmt.Println( "Client sent a bad request" )
+            resp = "te@error"       // set transaction end message
+        default:        // something undefined entirely
+            // TODO write out to file
+            //fmt.Println( "Message header not recognized" )
+            //fmt.Println( msg )
+            conn.Close()    // TODO how important is this line
+            return      // dead return, essentially lets program quit
+    }
+
+    // send formulated response back to server
+    _, err = conn.Write( []byte( resp ) )
+    check( err )    // make sure write worked
+
+    handle( conn )  // call handle again
+}
+
+
+// globals
+var qsize int       // keep track of num of quotes
+var conn net.Conn   // keep track of connection
+
+
+// global flag variables
+var add bool        // add new quotes to quote file ( on server )
+var remove bool     // remove quotes from quote file ( on server )
+var list bool       // request entire quote file from server
+var dest string     // provide a new destination ip and port
+
+
+func main() {
+
+    // define flags
+    flag.BoolVar( &add, "a", false, "add quote to list" )
+    flag.BoolVar( &remove, "r", false, "remove quote from list" )
+    flag.BoolVar( &list, "l", false, "print quote list" )
+    flag.StringVar( &dest, "ip", ":1300", "ip:port of server" )
+    flag.Parse()    // process flags
+
+    service := dest     // declare server ip:port
+
+    // create address object
+    addr, err := net.ResolveTCPAddr( "tcp", service )
+    check( err )    // check for errors
+
+    // make connection with object
+    conn, err = net.DialTCP( "tcp", nil, addr )
+    check( err )    // check for errors
+
+    // block for all flags
+    var command string
+    switch {        // empty switch statement is basically an if
+        case list:  // if list flag is active
+            command = "lr@dumvar"   // list request
+            // TODO come up with a useful argument, instead of dumvar
+        case add:   // if add flag is active
+            // if arguments were specified
+            if len( flag.Args() ) != 0 {
+                command = "ar@"     // preface command w/ add request
+                // need to concat flag.args
+                for _, v := range flag.Args() {
+                    // add the string and a space to command
+                    command = command + v + " "
+                }
+                // remove the trailing space
+                command = command[:len( command ) - 1]
+            } else {    // if no arguments were specified
+                // print that you need args and bail
+                fmt.Println( "/a/ flag must be used with an arugment" )
+                os.Exit( 1 )
+            }
+        case remove:    // if remove flag is active
+            // if arguments were specified
+            if len( flag.Args() ) > 0 {
+                // argument is supposed to the number of the quote to
+                // be removed, get first arg
+                // cast to int just to make sure it's a valid number
+                // assuming the user knows what they're doing
+                _, rerr := strconv.Atoi( flag.Args()[0] )
+                // if there was an error, just pretend there's no args
+                if rerr != nil {
+                    command = "r1@dumvar"   // remove request 1
+                    // TODO come up w/ useful argument, replace dumvar
+                } else {
+                    // if user knows the number, take care of it
+                    // arg[0] is a string, so concat is cool
+                    // jump right into remove request 2
+                    command = "r2@" + flag.Args()[0]
+                }
+            } else {    // if no argument was specified for remove
+                // jump right into remove request 1
+                command = "r1@dumvar"
+            }
+        default:    // if no flag was specified
+            // begin transaction for quote request
+            command = "sr@please"   // size request
+    }
+
+    // write command to server, beginning transaction
+    _, err = conn.Write( []byte( command ) )
+    check( err )    // make sure write worked
+
+    handle( conn )  // handle response
+    // TODO stack trace when handle returns, should probably be
+    // updated
+    conn.Close()    // close connection when finished
+
+    os.Exit( 0 )    // exit
+
+}
+

dev/seq/pieces/test.go

@@ -0,0 +1,126 @@
+// =============================================================================
+// Auth: Alex Celani
+// File: test.go
+// Revn: 05-13-2024  0.2
+// Func: explore bounding on piecewise file transmission ( PWFT )
+//
+// TODO: rewrite makedata() to write to a file
+//       write level4()
+// =============================================================================
+// CHANGE LOG
+// -----------------------------------------------------------------------------
+// 04-19-2024: bones
+//             level 0 PWFT
+//             level 1 PWFT
+//             level 2 PWFT
+// 05-13-2024: comment level 1 and level 2 PWFT
+//             level 3 PWFT
+//
+// =============================================================================
+
+package main
+
+import ( 
+    "fmt"
+    "math/rand"
+    "strconv"
+)
+
+func makedata() {
+    for c := 0; c < dsize; c++ {
+        datum[c] = rand.Intn( dsize )
+    }
+}
+
+// Levels of PWFT
+// 0. print everything indescriminately
+// 1. printing piecewise
+// 2. printing piecewise with header
+// 3. printing piecewise with variable size header
+// 4. file tx piecewise
+// 5. file tx piecewise with header
+// 6. file tx piecewise with variable header
+
+// level 0 PWFT
+func level0( data []int) {
+    fmt.Println( data )    // level 0 sux
+}
+
+
+// level 1 PWFT
+func level1() {
+    tsize := 5               // print 5 chars at a time
+    txn := dsize / tsize    // amount of prints needed
+    for c := 0; c < txn; c++ {      // iterate that amount of times
+        // print ( using wrapper ) n-1 data points of size tsize
+        level0( datum[c*tsize:(c+1)*tsize] )
+    }
+    level0( datum[txn*tsize:] )     // print nth data point
+}
+
+
+// level 2 PWFT
+func level2() {
+    var bsize int = 10              // total transmission size
+    var header string = "Lr@x@"     // static header
+    // calculate usable header size
+    var tsize int = bsize - len( header )
+    txn := dsize / tsize            // amount of prints needed
+    for c := 0; c < txn; c++ {      // iterate that amount of times
+        fmt.Print( header )         // print static header
+        // exact same print statement from level 1
+        level0( datum[c*tsize:(c+1)*tsize] )
+    }
+    fmt.Print( header )             // print nth static header
+    level0( datum[txn*tsize:] )     // print nth data point again
+}
+
+
+// level 3 PWFT
+func level3() {
+    var header string       // declare header
+    var bsize int = 10      // total transmission size
+    var hhead, htail string = "Lr@", "@"    // static pieces of header
+    txn := 1    // init transmission number
+    pos := 0    // init position tracker
+
+    for {   // easier to do an infinite loop and break later
+        // combine both static parts of the header with the tx number
+        header = hhead + strconv.Itoa( txn ) + htail
+        hlen := len( header )   // keep track of total header length
+        fmt.Print( header )     // print header
+
+        // level0 print ( bsize - hlen ) units of data, starting at
+        // the noted position
+        level0( datum[ pos:(pos + bsize - hlen) ] )
+        // update position as last position printed
+        pos = pos + bsize - hlen
+        txn++   // update transmission number
+
+        // check to see if *updated* position goes out of bounds
+        if pos + bsize - hlen > dsize {
+            break   // break if'n
+        }
+    }
+    // print nth header ( X denotes final transmission )
+    fmt.Print( hhead + "X" + htail )
+    level0( datum[pos:] )   // print from final position to end
+}
+
+
+
+// size variables
+var dsize int = 104
+// data global
+var datum = make( []int, dsize )
+
+
+func main() {
+    makedata()  // fill global with data
+
+    // print global data to show that PWFT works as intended
+    level0( datum )
+
+    level3()    // do the thing
+}
+

dev/seq/server.go

@@ -0,0 +1,281 @@
+// =============================================================================
+// Auth: Alex Celani
+// File: server.go
+// Revn: 10-17-2023  3.0
+// Func: host connection, reply to speak.go
+//
+// TODO: add more /codes/ to handle
+//       add flags?
+//       write usage and errors to logfile
+//       send logfile to client on request
+// =============================================================================
+// CHANGE LOG
+// -----------------------------------------------------------------------------
+// 05-13-2022: init
+// 08-29-2023: gutted and rewrote
+//             commented
+// 09-12-2023: imported io/ioutil, strings, strconv
+//             added size conversation
+//             added file read function, fread()
+//             commented
+// 09-21-2023: began rewrite of handle()
+// 09-26-2023: got /list/ command working
+//             got /add/ command (mostly) working
+//*10-02-2023: commented handle()
+//             added checks to /qr/ and /r2/ to make sure recv'd
+//              length is valid
+//             wrote writeFile()
+//*10-05-2023: commented
+//             imported check() to ignore EOF
+//             fixed bug in /r2/ where removing quote at final
+//              position would break
+//             removed deadcode from /r2/, unused "quit" bool?
+//*10-17-2023: fixed bug where quotes are read from and saved to two
+//              different files
+//             removed implicit newline at end of qfile to stop ghost
+//              line bug in /la/
+//             removed dead debug print in fread()
+//
+// =============================================================================
+
+package main
+
+import (
+    "fmt"       // Println
+    "io"        // io.EOF
+    "io/ioutil" // ReadFile
+    "net"       // ResovleTCPAddr, ListenTCP, listener.Accept
+                // conn.Read,Write
+    "os"        // Exit
+    "strconv"   // Itoa
+    "strings"   // Split
+)
+
+
+// handle errors catastrophically
+func check( err error ) {
+    if err != nil {    // error is not nil on error
+        // print error
+        fmt.Println( "Fatal: ", err.Error() )
+        os.Exit( 1 )    // bail
+    }
+}
+
+
+// FIXME clean this two check() shit up
+// print errors if they occur, quit
+func checkN( err error, conn net.Conn ) {
+
+    var errep string    // declare error report string
+    switch err {        // switch case over error input
+        case nil:       // if there was no error
+            // then there was no error
+            errep = "err is nil"
+        case io.EOF:    // if there was an End Of File error
+            errep = "Error: " + err.Error()     // document error
+            conn.Close()    // close connection
+        default:    // anything besides those are a big deal
+            errep = "Fatal: " + err.Error()
+    }
+
+    var critical bool   // declare critical error flag
+    // must be neither nil nor EOF
+    critical = err != nil && err != io.EOF
+    if critical {   // XXX critical print
+        // TODO at some point, critical should be logging instead of
+        // printing, only verbose should print
+        fmt.Println( "check() -> ", errep )
+    }
+    
+    if critical {       // if there was a critical error
+        os.Exit( 1 )    // cut and run
+    }
+}
+
+
+// read file and create quote list
+func fread() string {
+    // open file "quotes", read entire file as bytes into qfile
+    qfile, err := ioutil.ReadFile( "list.q" )
+    check( err )    // make sure read works
+    // there is a trailing newline in the file, not removing it caused
+    // bugs where a blank item was introduced into qlist and calling
+    // /la/ would produce a blank line on the client side that didn't
+    // really exist
+    qfile = qfile[:len( qfile ) - 1]
+    // cast bytes to string, split string over newline into array
+    qlist = strings.Split( string( qfile ), "\n" )
+    // deal with the trailing
+    return string( qfile )      // return file as string
+}
+
+
+// write qfile back to file
+func writeFile( f string ) {
+    // open file list.q as variable file
+    file, err := os.Create( "list.q" )
+    check( err )    // make sure open worked
+    // write input string ( quote file ) back to file
+    _, err = file.WriteString( f )
+    check( err )    // make sure writeback worked
+}
+
+
+// handle connections ( new and improved )
+func handle( conn net.Conn ) {
+
+    // create buffer to hold read message
+    var buffer [256]byte
+    // read n bytes from client
+    n, err := conn.Read( buffer[:] )
+    checkN( err, conn ) // make sure read worked
+
+    // cast message to string, take first n bytes, split over @
+    command := strings.Split( string( buffer[:n] ), "@" )
+
+    // declare response string
+    var resp string
+    switch command[0] {     // switch/case over opcode
+        case "sr":      // /sr/, size request
+            // get length of list, convert to string
+            // XXX probably no reason to have this declaration scheme
+            var num string = strconv.Itoa( len( qlist ) )
+            // concat and send
+            resp = "sa@" + num      // size answer
+        case "qr":      // /qr/, quote request
+            // convert message argument to string to make sure it's a
+            // valid number
+            num, nerr := strconv.Atoi( command[1] )
+            // nerr will not be nil if comm[1] is not a number
+            if nerr != nil {
+                // formulate an error message
+                // TODO flesh this out more
+                resp = "ba@qr@!"    // bad answer
+            } else {        // comm[1] was a number, but...
+                switch {    // how do we know it's a valid number
+                    case num > len( qlist ):
+                        // bad answer in quote request
+                        resp = "ba@qr@>"
+                        // why bad? num is >
+                    case num < 0:
+                        // bad answer in quote request
+                        resp = "ba@qr@-"
+                        // why bad? num is -
+                    default:
+                        // good num, get quote, send off
+                        resp = "qa@" + qlist[num]   // quote answer
+                }
+            }
+        case "lr":      // /lr/, list request
+            // just concat entire list to send
+            //resp = "la@" + qfile[:len( qfile ) - 1]     // list answer
+            resp = "la@" + qfile    // list answer
+            // TODO what happens if this is longer than 256 char?
+        case "ar":      // /ar/, add request
+            // append new quote to list
+            qlist = append( qlist, command[1] )
+            // also append new quote to file variable
+            qfile = qfile + "\n" + command[1]
+            writeFile( qfile )
+            resp = "aa@success"     // add answer
+            // TODO write to file
+        case "r1":      // /r1/, remove request 1
+            // same as list, just send whole file
+            resp = "r1@" + qfile    // remove request 1
+        case "r2":      // /r2/, remove request 2
+            // convert message argument to string to make sure it's a
+            // valid number
+            num, nerr := strconv.Atoi( command[1] )
+            // nerr will not be nil if comm[1] is not a number
+            if nerr != nil {
+                // formulate an error message
+                // TODO flesh this out more
+                resp = "ba@r2@!"    // bad answer
+            } else {        // comm[1] was a number, but...
+                num = num - 1
+                switch {    // how do we know it's a valid number
+                            // valid numbers are from 0 - len-1
+                    case num > len( qlist ):
+                        // bad answer in quote request
+                        resp = "ba@r2@>"
+                        // why bad? num is >
+                    case num < 0:
+                        // bad answer in quote request
+                        resp = "ba@r2@-"
+                        // why bad? num is -
+                    // if num is not OUT OF RANGE, must be in range
+                    default:
+                        // replace the quote at that position with
+                        // final quote
+                        qlist[num] = qlist[len( qlist ) - 1]
+                        // remove second copy of quote
+                        qlist = qlist[:len( qlist ) - 1]
+                        // O(1) remove from list at any position
+                        // must entirely recreate quote string
+                        var f string = ""   // init empty string
+                        // iterate over list, disregard index
+                        for _, v := range qlist {
+                            // add next quote to file and separate
+                            // quotes with newline
+                            f = f + v + "\n"
+                        }
+                        // remove trailing newline, to prevent ghost
+                        f = f[:len( f ) - 1]    // quote in lr
+                        // reassign global string variable to
+                        // recreated quote string
+                        qfile = f
+                        writeFile( qfile )  // write back to file
+                        // let client know remove was successful
+                        resp = "r2@success"
+                }
+            }
+        case "te":      // /te/, transaction end
+            // TODO should I be sending something?
+            // TODO is it better to close now or outside of handle()
+            conn.Close()    // close connection and leave
+            return          // return from handle(), finish connection
+        default:        // opcode not recognized
+            // TODO there should be more being down, here, right?
+            return          // return from handle(), finish connection
+    }
+
+    // write response to client
+    _, err = conn.Write( []byte( resp ) )
+    checkN( err, conn ) // make sure write worked
+
+    handle( conn )  // call handle() again to get response from client
+
+}
+
+
+// globals
+var qlist []string      // list of quotes
+var qfile string        // file object
+
+
+// main, create port and wait for connection
+func main() {
+
+    qfile = fread() // read quote file, init ( global ) list of quotes
+
+    service := ":1300"  // create service on ip and port
+
+    // resolve ip address and port
+    addr, err := net.ResolveTCPAddr( "tcp", service )
+    check( err )    // make sure ip resolves
+
+    // create listener object from ip:port
+    listener, err := net.ListenTCP( "tcp", addr )
+
+    for {
+        // wait, create connection when found
+        conn, err := listener.Accept()
+        check( err )    // make sure connection works
+    
+        go handle( conn )  // handle connection
+    }
+
+    os.Exit( 0 )    // exeunt
+
+}
+