Add scripting (tengo) support for every incoming message (#731)

TengoModifyMessage allows you to specify the location of a tengo (https://github.com/d5/tengo/) script.
This script will receive every incoming message and can be used to modify the Username and the Text of that message.
The script will have the following global variables:
to modify: msgUsername and msgText
to read: msgChannel and msgAccount

The script is reloaded on every message, so you can modify the script on the fly.

Example script can be found in https://github.com/42wim/matterbridge/tree/master/gateway/bench.tengo
and https://github.com/42wim/matterbridge/tree/master/contrib/example.tengo

The example below will check if the text contains blah and if so, it'll replace the text and the username of that message.
text := import("text")
if text.re_match("blah",msgText) {
    msgText="replaced by this"
    msgUsername="fakeuser"
}

More information about tengo on: https://github.com/d5/tengo/blob/master/docs/tutorial.md and
https://github.com/d5/tengo/blob/master/docs/stdlib.md

1 files changed, 195 insertions, 0 deletions

diff --git a/vendor/github.com/d5/tengo/stdlib/text_regexp.go b/vendor/github.com/d5/tengo/stdlib/text_regexp.go
new file mode 100644
index 00000000..3fb8b3b3
--- /dev/null
+++ b/vendor/github.com/d5/tengo/stdlib/text_regexp.go
@@ -0,0 +1,195 @@
+package stdlib
+
+import (
+	"regexp"
+
+	"github.com/d5/tengo/objects"
+)
+
+func makeTextRegexp(re *regexp.Regexp) *objects.ImmutableMap {
+	return &objects.ImmutableMap{
+		Value: map[string]objects.Object{
+			// match(text) => bool
+			"match": &objects.UserFunction{
+				Value: func(args ...objects.Object) (ret objects.Object, err error) {
+					if len(args) != 1 {
+						err = objects.ErrWrongNumArguments
+						return
+					}
+
+					s1, ok := objects.ToString(args[0])
+					if !ok {
+						err = objects.ErrInvalidArgumentType{
+							Name:     "first",
+							Expected: "string(compatible)",
+							Found:    args[0].TypeName(),
+						}
+						return
+					}
+
+					if re.MatchString(s1) {
+						ret = objects.TrueValue
+					} else {
+						ret = objects.FalseValue
+					}
+
+					return
+				},
+			},
+
+			// find(text) 			=> array(array({text:,begin:,end:}))/undefined
+			// find(text, maxCount) => array(array({text:,begin:,end:}))/undefined
+			"find": &objects.UserFunction{
+				Value: func(args ...objects.Object) (ret objects.Object, err error) {
+					numArgs := len(args)
+					if numArgs != 1 && numArgs != 2 {
+						err = objects.ErrWrongNumArguments
+						return
+					}
+
+					s1, ok := objects.ToString(args[0])
+					if !ok {
+						err = objects.ErrInvalidArgumentType{
+							Name:     "first",
+							Expected: "string(compatible)",
+							Found:    args[0].TypeName(),
+						}
+						return
+					}
+
+					if numArgs == 1 {
+						m := re.FindStringSubmatchIndex(s1)
+						if m == nil {
+							ret = objects.UndefinedValue
+							return
+						}
+
+						arr := &objects.Array{}
+						for i := 0; i < len(m); i += 2 {
+							arr.Value = append(arr.Value, &objects.ImmutableMap{Value: map[string]objects.Object{
+								"text":  &objects.String{Value: s1[m[i]:m[i+1]]},
+								"begin": &objects.Int{Value: int64(m[i])},
+								"end":   &objects.Int{Value: int64(m[i+1])},
+							}})
+						}
+
+						ret = &objects.Array{Value: []objects.Object{arr}}
+
+						return
+					}
+
+					i2, ok := objects.ToInt(args[1])
+					if !ok {
+						err = objects.ErrInvalidArgumentType{
+							Name:     "second",
+							Expected: "int(compatible)",
+							Found:    args[1].TypeName(),
+						}
+						return
+					}
+					m := re.FindAllStringSubmatchIndex(s1, i2)
+					if m == nil {
+						ret = objects.UndefinedValue
+						return
+					}
+
+					arr := &objects.Array{}
+					for _, m := range m {
+						subMatch := &objects.Array{}
+						for i := 0; i < len(m); i += 2 {
+							subMatch.Value = append(subMatch.Value, &objects.ImmutableMap{Value: map[string]objects.Object{
+								"text":  &objects.String{Value: s1[m[i]:m[i+1]]},
+								"begin": &objects.Int{Value: int64(m[i])},
+								"end":   &objects.Int{Value: int64(m[i+1])},
+							}})
+						}
+
+						arr.Value = append(arr.Value, subMatch)
+					}
+
+					ret = arr
+
+					return
+				},
+			},
+
+			// replace(src, repl) => string
+			"replace": &objects.UserFunction{
+				Value: func(args ...objects.Object) (ret objects.Object, err error) {
+					if len(args) != 2 {
+						err = objects.ErrWrongNumArguments
+						return
+					}
+
+					s1, ok := objects.ToString(args[0])
+					if !ok {
+						err = objects.ErrInvalidArgumentType{
+							Name:     "first",
+							Expected: "string(compatible)",
+							Found:    args[0].TypeName(),
+						}
+						return
+					}
+
+					s2, ok := objects.ToString(args[1])
+					if !ok {
+						err = objects.ErrInvalidArgumentType{
+							Name:     "second",
+							Expected: "string(compatible)",
+							Found:    args[1].TypeName(),
+						}
+						return
+					}
+
+					ret = &objects.String{Value: re.ReplaceAllString(s1, s2)}
+
+					return
+				},
+			},
+
+			// split(text) 			 => array(string)
+			// split(text, maxCount) => array(string)
+			"split": &objects.UserFunction{
+				Value: func(args ...objects.Object) (ret objects.Object, err error) {
+					numArgs := len(args)
+					if numArgs != 1 && numArgs != 2 {
+						err = objects.ErrWrongNumArguments
+						return
+					}
+
+					s1, ok := objects.ToString(args[0])
+					if !ok {
+						err = objects.ErrInvalidArgumentType{
+							Name:     "first",
+							Expected: "string(compatible)",
+							Found:    args[0].TypeName(),
+						}
+						return
+					}
+
+					var i2 = -1
+					if numArgs > 1 {
+						i2, ok = objects.ToInt(args[1])
+						if !ok {
+							err = objects.ErrInvalidArgumentType{
+								Name:     "second",
+								Expected: "int(compatible)",
+								Found:    args[1].TypeName(),
+							}
+							return
+						}
+					}
+
+					arr := &objects.Array{}
+					for _, s := range re.Split(s1, i2) {
+						arr.Value = append(arr.Value, &objects.String{Value: s})
+					}
+
+					ret = arr
+
+					return
+				},
+			},
+		},
+	}
+}