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* add local spam filter * optimize, don't tokenize spam samples on each check * simplify spam params
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,129 @@ | ||
| package bot | ||
|
|
||
| import ( | ||
| "bufio" | ||
| "fmt" | ||
| "io" | ||
| "log" | ||
| "math" | ||
| "strings" | ||
| ) | ||
|
|
||
| // SpamLocalFilter bot, checks if user is a spammer using internal matching | ||
| type SpamLocalFilter struct { | ||
| dry bool | ||
| superUser SuperUser | ||
| threshold float64 | ||
|
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| enabled bool | ||
| tokenizedSpam []map[string]int | ||
| approvedUsers map[int64]bool | ||
| } | ||
|
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| // NewSpamLocalFilter makes a spam detecting bot | ||
| func NewSpamLocalFilter(spamSamples io.Reader, threshold float64, superUser SuperUser, dry bool) *SpamLocalFilter { | ||
| log.Printf("[INFO] Spam bot (local), threshold=%0.2f", threshold) | ||
| res := &SpamLocalFilter{dry: dry, approvedUsers: map[int64]bool{}, superUser: superUser, threshold: threshold} | ||
|
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| scanner := bufio.NewScanner(spamSamples) | ||
| for scanner.Scan() { | ||
| tokenizedSpam := res.tokenize(scanner.Text()) | ||
| res.tokenizedSpam = append(res.tokenizedSpam, tokenizedSpam) | ||
| } | ||
| if err := scanner.Err(); err != nil { | ||
| log.Printf("[WARN] failed to read spam samples, error=%v", err) | ||
| res.enabled = false | ||
| } else { | ||
| res.enabled = true | ||
| } | ||
| return res | ||
| } | ||
|
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| // OnMessage checks if user already approved and if not checks if user is a spammer | ||
| func (s *SpamLocalFilter) OnMessage(msg Message) (response Response) { | ||
| if !s.enabled { | ||
| return Response{} | ||
| } | ||
|
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| if s.approvedUsers[msg.From.ID] { | ||
| return Response{} | ||
| } | ||
|
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| if s.superUser.IsSuper(msg.From.Username) { | ||
| return Response{} // don't check super users for spam | ||
| } | ||
|
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| if !s.isSpam(msg.Text) { | ||
| log.Printf("[INFO] user %s is not a spammer, added to aproved", msg.From.Username) | ||
| s.approvedUsers[msg.From.ID] = true | ||
| return Response{} // not a spam | ||
| } | ||
|
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| log.Printf("[INFO] user %s detected as spammer, msg: %q", msg.From.Username, msg.Text) | ||
| if s.dry { | ||
| return Response{ | ||
| Text: fmt.Sprintf("this is spam from %q, but I'm in dry mode, so I'll do nothing yet", msg.From.Username), | ||
| Send: true, ReplyTo: msg.ID, | ||
| } | ||
| } | ||
| return Response{Text: "this is spam! go to ban, " + msg.From.DisplayName, Send: true, ReplyTo: msg.ID, BanInterval: permanentBanDuration, DeleteReplyTo: true} | ||
| } | ||
|
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| // Help returns help message | ||
| func (s *SpamLocalFilter) Help() string { return "" } | ||
|
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| // ReactOn keys | ||
| func (s *SpamLocalFilter) ReactOn() []string { return []string{} } | ||
|
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| // isSpam checks if a given message is similar to any of the known bad messages. | ||
| func (s *SpamLocalFilter) isSpam(message string) bool { | ||
| tokenizedMessage := s.tokenize(message) | ||
| maxSimilarity := 0.0 | ||
| for _, spam := range s.tokenizedSpam { | ||
| similarity := s.cosineSimilarity(tokenizedMessage, spam) | ||
| if similarity > maxSimilarity { | ||
| maxSimilarity = similarity | ||
| } | ||
| if similarity >= s.threshold { | ||
| return true | ||
| } | ||
| } | ||
| log.Printf("[DEBUG] spam similarity: %0.2f", maxSimilarity) | ||
| return false | ||
| } | ||
|
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||
| // tokenize takes a string and returns a map where the keys are unique words (tokens) | ||
| // and the values are the frequencies of those words in the string. | ||
| func (s *SpamLocalFilter) tokenize(inp string) map[string]int { | ||
| tokenFrequency := make(map[string]int) | ||
| tokens := strings.Fields(inp) | ||
| for _, token := range tokens { | ||
| tokenFrequency[strings.ToLower(token)]++ | ||
| } | ||
| return tokenFrequency | ||
| } | ||
|
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| // cosineSimilarity calculates the cosine similarity between two token frequency maps. | ||
| func (s *SpamLocalFilter) cosineSimilarity(a, b map[string]int) float64 { | ||
| if len(a) == 0 || len(b) == 0 { | ||
| return 0.0 | ||
| } | ||
|
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| dotProduct := 0 // sum of product of corresponding frequencies | ||
| normA, normB := 0, 0 // square root of sum of squares of frequencies | ||
|
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| for key, val := range a { | ||
| dotProduct += val * b[key] | ||
| normA += val * val | ||
| } | ||
| for _, val := range b { | ||
| normB += val * val | ||
| } | ||
|
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| if normA == 0 || normB == 0 { | ||
| return 0.0 | ||
| } | ||
|
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| // cosine similarity formula | ||
| return float64(dotProduct) / (math.Sqrt(float64(normA)) * math.Sqrt(float64(normB))) | ||
| } |
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,70 @@ | ||
| package bot | ||
|
|
||
| import ( | ||
| "strings" | ||
| "testing" | ||
|
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| "github.com/stretchr/testify/assert" | ||
|
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| "github.com/radio-t/super-bot/app/bot/mocks" | ||
| ) | ||
|
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| func TestSpamLocalFilter_OnMessage(t *testing.T) { | ||
| superUser := &mocks.SuperUser{IsSuperFunc: func(userName string) bool { | ||
| if userName == "super" || userName == "admin" { | ||
| return true | ||
| } | ||
| return false | ||
| }} | ||
| spamSamples := strings.NewReader("win free iPhone\nlottery prize") | ||
|
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| filter := NewSpamLocalFilter(spamSamples, 0.5, superUser, false) | ||
|
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| tests := []struct { | ||
| msg Message | ||
| expected Response | ||
| }{ | ||
| { | ||
| Message{From: User{ID: 1, Username: "john", DisplayName: "John"}, Text: "Hello, how are you?", ID: 1}, | ||
| Response{}, | ||
| }, | ||
| { | ||
| Message{From: User{ID: 2, Username: "spammer", DisplayName: "Spammer"}, Text: "Win a free iPhone now!", ID: 2}, | ||
| Response{Text: "this is spam! go to ban, Spammer", Send: true, ReplyTo: 2, BanInterval: permanentBanDuration, DeleteReplyTo: true}, | ||
| }, | ||
| { | ||
| Message{From: User{ID: 3, Username: "super", DisplayName: "SuperUser"}, Text: "Win a free iPhone now!", ID: 3}, | ||
| Response{}, | ||
| }, | ||
| } | ||
|
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| for _, test := range tests { | ||
| assert.Equal(t, test.expected, filter.OnMessage(test.msg)) | ||
| } | ||
| } | ||
|
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| func TestIsSpam(t *testing.T) { | ||
| spamSamples := strings.NewReader("win free iPhone\nlottery prize") | ||
| filter := NewSpamLocalFilter(spamSamples, 0.5, nil, false) // SuperUser set to nil for this test | ||
|
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| tests := []struct { | ||
| name string | ||
| message string | ||
| threshold float64 | ||
| expected bool | ||
| }{ | ||
| {"Not Spam", "Hello, how are you?", 0.5, false}, | ||
| {"Exact Match", "Win a free iPhone now!", 0.5, true}, | ||
| {"Similar Match", "You won a lottery prize!", 0.3, true}, | ||
| {"High Threshold", "You won a lottery prize!", 0.9, false}, | ||
| {"Partial Match", "win free", 0.9, false}, | ||
| {"Low Threshold", "win free", 0.8, true}, | ||
| } | ||
|
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| for _, test := range tests { | ||
| t.Run(test.name, func(t *testing.T) { | ||
| filter.threshold = test.threshold // Update threshold for each test case | ||
| assert.Equal(t, test.expected, filter.isSpam(test.message)) | ||
| }) | ||
| } | ||
| } |
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