From 308d1b607313f033453b65621a2a8c490de990f0 Mon Sep 17 00:00:00 2001
From: Jan-Lukas Else <mail@jlelse.de>
Date: Sun, 22 Mar 2020 10:43:45 +0100
Subject: [PATCH] Blacklist

---
 README.md         |  1 +
 config.go         |  1 +
 config_test.go    |  7 +++++++
 spamcheck.go      | 16 +++++++++++++++-
 spamcheck_test.go | 26 ++++++++++++++++++++++++++
 5 files changed, 50 insertions(+), 1 deletion(-)
 create mode 100644 spamcheck_test.go

diff --git a/README.md b/README.md
index a64889a..1c001da 100644
--- a/README.md
+++ b/README.md
@@ -30,6 +30,7 @@ To run the server, you must set a few environment variables from the list below.
 | **`PORT`** | optional | `8080` | The port on which the server should listen |
 | **`HONEYPOTS`** | optional | `_t_email` | Honeypot form fields (separated by `,`) |
 | **`GOOGLE_API_KEY`** | optional | - | Google API Key for the [Google Safe Browsing API](https://developers.google.com/safe-browsing/v4/) |
+| **`BLACKLIST`** | optional | `gambling,casino` | List of spam words |
 
 ## Special form fields
 
diff --git a/config.go b/config.go
index fd83d7d..4c7bb05 100644
--- a/config.go
+++ b/config.go
@@ -16,6 +16,7 @@ type config struct {
 	SmtpHost          string   `env:"SMTP_HOST"`
 	SmtpPort          int      `env:"SMTP_PORT" envDefault:"587"`
 	GoogleApiKey      string   `env:"GOOGLE_API_KEY"`
+	Blacklist         []string `env:"BLACKLIST" envSeparator:"," envDefault:"gambling,casino"`
 }
 
 func parseConfig() (config, error) {
diff --git a/config_test.go b/config_test.go
index 3dfdf3e..083b78e 100644
--- a/config_test.go
+++ b/config_test.go
@@ -23,6 +23,9 @@ func Test_parseConfig(t *testing.T) {
 		if cfg.SmtpPort != 587 {
 			t.Error("SMTP Port not 587")
 		}
+		if len(cfg.Blacklist) != 2 || cfg.Blacklist[0] != "gambling" || cfg.Blacklist[1] != "casino" {
+			t.Error("Default Blacklist is wrong")
+		}
 	})
 	t.Run("Correct config parsing", func(t *testing.T) {
 		os.Clearenv()
@@ -36,6 +39,7 @@ func Test_parseConfig(t *testing.T) {
 		_ = os.Setenv("SMTP_HOST", "smtp.example.com")
 		_ = os.Setenv("SMTP_PORT", "100")
 		_ = os.Setenv("GOOGLE_API_KEY", "abc")
+		_ = os.Setenv("BLACKLIST", "test,abc")
 		cfg, err := parseConfig()
 		if err != nil {
 			t.Error()
@@ -71,6 +75,9 @@ func Test_parseConfig(t *testing.T) {
 		if !reflect.DeepEqual(cfg.GoogleApiKey, "abc") {
 			t.Error("Google API Key is wrong")
 		}
+		if !reflect.DeepEqual(cfg.Blacklist, []string{"test", "abc"}) {
+			t.Error("Blacklist is wrong")
+		}
 	})
 	t.Run("Error when wrong config", func(t *testing.T) {
 		os.Clearenv()
diff --git a/spamcheck.go b/spamcheck.go
index cd4f1f7..9ac482f 100644
--- a/spamcheck.go
+++ b/spamcheck.go
@@ -9,8 +9,10 @@ import (
 // Returns true when it spam
 func checkValues(values FormValues) bool {
 	var urlsToCheck []string
+	var allValues []string
 	for _, value := range values {
 		for _, singleValue := range value {
+			allValues = append(allValues, singleValue)
 			if strings.Contains(singleValue, "http") {
 				parsed, e := url.Parse(singleValue)
 				if parsed != nil && e == nil {
@@ -19,7 +21,19 @@ func checkValues(values FormValues) bool {
 			}
 		}
 	}
-	return checkUrls(urlsToCheck)
+	return checkBlacklist(allValues) || checkUrls(urlsToCheck)
+}
+
+func checkBlacklist(values []string) bool {
+	for _, value := range values {
+		for _, blacklistedString := range appConfig.Blacklist {
+			if strings.Contains(strings.ToLower(value), strings.ToLower(blacklistedString)) {
+				return true
+			}
+		}
+
+	}
+	return false
 }
 
 // Only tests when GOOGLE_API_KEY is set
diff --git a/spamcheck_test.go b/spamcheck_test.go
new file mode 100644
index 0000000..5b75282
--- /dev/null
+++ b/spamcheck_test.go
@@ -0,0 +1,26 @@
+package main
+
+import (
+	"os"
+	"testing"
+)
+
+func Test_checkBlacklist(t *testing.T) {
+	prepare := func() {
+		os.Clearenv()
+		_ = os.Setenv("BLACKLIST", "test1,test2")
+		appConfig, _ = parseConfig()
+	}
+	t.Run("Allowed values", func(t *testing.T) {
+		prepare()
+		if checkBlacklist([]string{"Hello", "How are you?"}) == true {
+			t.Error()
+		}
+	})
+	t.Run("Forbidden values", func(t *testing.T) {
+		prepare()
+		if checkBlacklist([]string{"How are you?", "Hello TeSt1"}) == false {
+			t.Error()
+		}
+	})
+}