Add possibility to provide parameters via command

Author: wilriker

README.md

@@ -16,6 +16,28 @@ Usage of ./execonmcode:
         Path to socket (default "/var/run/duet.sock")
 ```
 
+## Parameters
+`execonmcode` does provide a simple mechanism for parameter substitution. It is possible to pass string parameters to the
+selected `M-Code` and have them inserted in the `-command`. In the command string they have to be single letters prefixed by
+the percent-sign (`%`) and they must not be `G`, `M` or `T`.
+
+All parameters that do not have a corresponding value in the `M-Code` will be forwarded as given.
+
+### Example
+Run `execonmcode` as
+```
+$ ./execonmcode -command "mycommand %F %N %D"
+```
+Then you can use the following `M-Code` syntax to replace these parameters
+```
+M7722 F"my first parameter" N"my second parameter"
+```
+this will lead to an execution of
+```
+mycommand "my first parameter" "my second parameter" %D
+```
+Note that `%D` was passed as is since it was not given in the `M-Code`.
+
 # Installation
 * Download
 * Rename to just `execonmcode`

executor.go

@@ -5,11 +5,16 @@ import (
 	"os/exec"
 	"strings"
 
+	"github.com/wilriker/goduetapiclient/commands"
 	"github.com/wilriker/goduetapiclient/connection"
 	"github.com/wilriker/goduetapiclient/connection/initmessages"
 	"github.com/wilriker/goduetapiclient/types"
 )
 
+const (
+	variablePrefix = "%"
+)
+
 type Executor struct {
 	socketPath string
 	mCode      int64
@@ -48,7 +53,7 @@ func (e *Executor) Run() {
 			continue
 		}
 		if c.Type == types.MCode && c.MajorNumber != nil && *c.MajorNumber == e.mCode {
-			cmd := exec.Command(e.command, e.args...)
+			cmd := exec.Command(e.command, e.getArgs(c)...)
 			err := cmd.Run()
 			if err != nil {
 				err = ic.ResolveCode(types.Error, err.Error())
@@ -63,3 +68,19 @@ func (e *Executor) Run() {
 		}
 	}
 }
+
+func (e *Executor) getArgs(c *commands.Code) []string {
+	args := make([]string, len(e.args))
+	for _, v := range e.args {
+		if strings.HasPrefix(v, variablePrefix) {
+			vl := strings.TrimSpace(strings.ToUpper(strings.TrimLeft(v, variablePrefix)))
+			if len(vl) == 1 {
+				if pv := c.Parameter(vl); pv != nil {
+					v = pv.AsString()
+				}
+			}
+		}
+		args = append(args, v)
+	}
+	return args
+}

go.mod

@@ -2,4 +2,4 @@ module github.com/wilriker/execonmcode
 
 go 1.13
 
-require github.com/wilriker/goduetapiclient v0.0.0-20191014112126-94a17c5b2e4c
+require github.com/wilriker/goduetapiclient v0.0.0-20191213105344-41ea5d36085a

go.sum

@@ -1,2 +1,4 @@
 github.com/wilriker/goduetapiclient v0.0.0-20191014112126-94a17c5b2e4c h1:kbeSWusNKHJYqPLLUn3UqBsgUw+fqTLGBYqhiVfCvhQ=
 github.com/wilriker/goduetapiclient v0.0.0-20191014112126-94a17c5b2e4c/go.mod h1:KSadGbt2Z/wbyhZoh3I+Zp0me9YqrLhAPrAjH9J8OLM=
+github.com/wilriker/goduetapiclient v0.0.0-20191213105344-41ea5d36085a h1:jlWEyWAq7VTVxZo6SxywPjmZkEanBFhnfvzwgmh5KxA=
+github.com/wilriker/goduetapiclient v0.0.0-20191213105344-41ea5d36085a/go.mod h1:KSadGbt2Z/wbyhZoh3I+Zp0me9YqrLhAPrAjH9J8OLM=