Sanitizing Genesys Cloud Web Messaging Inputs with Go

What You Will Build

• A Go-based input sanitization gateway that validates, cleans, and forwards web messaging payloads to the Genesys Cloud Web Chat API.
• This implementation uses the official Genesys Cloud Go SDK and real HTTP endpoints.
• The tutorial covers Go 1.21+ with structured logging, context timeouts, and exponential backoff retry logic.

Prerequisites

• OAuth 2.0 Client Credentials grant configured in Genesys Cloud
• Required scopes: webchat:session:read, webchat:session:write
• Go 1.21 or later installed
• External dependencies: github.com/mygenesys/genesyscloud-sdk-go, golang.org/x/text, golang.org/x/net/html
• Environment variables: GENESYS_CLIENT_ID, GENESYS_CLIENT_SECRET, GENESYS_BASE_URL (default: https://api.mypurecloud.com), WAF_WEBHOOK_URL

Authentication Setup

Genesys Cloud requires OAuth 2.0 authentication for all API calls. The official Go SDK handles token acquisition and refresh when configured with client credentials. You must initialize the configuration object before creating the API client.

package main

import (
    "fmt"
    "os"

    "github.com/mygenesys/genesyscloud-sdk-go/platform/client"
    "github.com/mygenesys/genesyscloud-sdk-go/platform/clientconfiguration"
    "github.com/mygenesys/genesyscloud-sdk-go/platform/webchat"
)

func initializeGenesysClient() (*webchat.WebChatApi, error) {
    config, err := clientconfiguration.NewConfiguration()
    if err != nil {
        return nil, fmt.Errorf("failed to create Genesys configuration: %w", err)
    }

    config.SetClientId(os.Getenv("GENESYS_CLIENT_ID"))
    config.SetClientSecret(os.Getenv("GENESYS_CLIENT_SECRET"))
    
    baseUrl := os.Getenv("GENESYS_BASE_URL")
    if baseUrl == "" {
        baseUrl = "https://api.mypurecloud.com"
    }
    config.SetBasePath(baseUrl)

    apiClient := client.NewAPIClient(config)
    return webchat.NewWebChatApi(apiClient), nil
}

The SDK automatically manages the OAuth token lifecycle. It fetches a new access token using the client credentials grant and caches it until expiration. If a request returns a 401 Unauthorized, the SDK refreshes the token and retries the request automatically.

Implementation

Step 1: Construct Sanitizing Payloads with Input Reference and Clean Directive

You must define a sanitization matrix that maps incoming fields to cleaning rules. The matrix enforces maximum sanitization time limits, validates against messaging constraints, and applies XSS and SQL injection patterns.

package main

import (
    "context"
    "fmt"
    "regexp"
    "time"
    "golang.org/x/text/unicode/norm"
    "golang.org/x/net/html"
    "golang.org/x/net/html/atom"
)

type InputRef struct {
    FieldName string
    MaxLength int
    AllowHTML bool
}

type CleanDirective struct {
    StripTags       bool
    EncodeEntities  bool
    MaxSanitizationTime time.Duration
}

type MessagingMatrix struct {
    Rules []InputRef
    Directive CleanDirective
}

var (
    xssRegex = regexp.MustCompile(`(?i)<script[^>]*>|javascript:|on\w+\s*=`)
    sqlInjectionRegex = regexp.MustCompile(`(?i)(\b(SELECT|INSERT|UPDATE|DELETE|DROP|UNION|ALTER)\b|;|--|\bOR\b\s+\d+\s*=\s*\d+)`)
)

func SanitizePayload(ctx context.Context, rawPayload map[string]string, matrix MessagingMatrix) (map[string]string, error) {
    ctx, cancel := context.WithTimeout(ctx, matrix.Directive.MaxSanitizationTime)
    defer cancel()

    cleaned := make(map[string]string)

    for _, rule := range matrix.Rules {
        rawValue, exists := rawPayload[rule.FieldName]
        if !exists {
            continue
        }

        select {
        case <-ctx.Done():
            return nil, fmt.Errorf("sanitization exceeded maximum time limit for field %s", rule.FieldName)
        default:
        }

        // Malformed Unicode checking
        if !norm.NFC.IsNormalizedString(rawValue) {
            rawValue = norm.NFC.String(rawValue)
        }

        // Payload injection verification pipeline
        if len(rawValue) > rule.MaxLength {
            return nil, fmt.Errorf("field %s exceeds maximum length constraint", rule.FieldName)
        }

        // XSS regex calculation
        if xssRegex.MatchString(rawValue) {
            if rule.AllowHTML {
                // Sanitize HTML nodes instead of blocking
                doc, err := html.Parse(strings.NewReader(rawValue))
                if err != nil {
                    return nil, fmt.Errorf("HTML parsing failed: %w", err)
                }
                rawValue = sanitizeHTMLNodes(doc)
            } else {
                return nil, fmt.Errorf("XSS pattern detected in field %s", rule.FieldName)
            }
        }

        // SQL injection evaluation logic
        if sqlInjectionRegex.MatchString(rawValue) {
            return nil, fmt.Errorf("SQL injection pattern detected in field %s", rule.FieldName)
        }

        cleaned[rule.FieldName] = rawValue
    }

    return cleaned, nil
}

func sanitizeHTMLNodes(n *html.Node) string {
    var buf strings.Builder
    var walk func(*html.Node)
    walk = func(node *html.Node) {
        if node.Type == html.ElementNode {
            safe := atom.Text
            for _, a := range []atom.Atom{atom.Strong, atom.Em, atom.Code, atom.Br, atom.P} {
                if node.DataAtom == a {
                    safe = node.DataAtom
                    break
                }
            }
            if safe == atom.Text && node.DataAtom != atom.Text {
                // Skip unsafe tags
                return
            }
            buf.WriteString("<" + node.Data)
            for _, attr := range node.Attr {
                if attr.Key == "onload" || attr.Key == "onclick" || attr.Key == "style" {
                    continue
                }
                buf.WriteString(" " + attr.Key + "=\"" + attr.Val + "\"")
            }
            buf.WriteString(">")
        } else if node.Type == html.TextNode {
            buf.WriteString(node.Data)
        }
        for c := node.FirstChild; c != nil; c = c.NextSibling {
            walk(c)
        }
        if node.Type == html.ElementNode && node.DataAtom != atom.Text {
            buf.WriteString("</" + node.Data + ">")
        }
    }
    walk(n)
    return buf.String()
}

Step 2: Atomic HTTP POST Operations with Format Verification and Retry Logic

You must forward the sanitized payload to Genesys Cloud using atomic HTTP POST operations. The Web Chat API endpoint is /api/v2/webchat/sessions/{sessionId}/messages. You must implement exponential backoff for 429 Too Many Requests responses and verify the response format.

package main

import (
    "context"
    "fmt"
    "math"
    "time"

    "github.com/mygenesys/genesyscloud-sdk-go/platform/webchat"
)

type SanitizationAudit struct {
    Timestamp        time.Time
    SessionID        string
    Field            string
    OriginalLength   int
    CleanedLength    int
    SanitizationTime time.Duration
    Success          bool
    Error            string
}

func ForwardToGenesys(ctx context.Context, api *webchat.WebChatApi, sessionID string, cleanedPayload map[string]string, audit *SanitizationAudit) error {
    // Construct Genesys Cloud message body
    body := &webchat.WebchatMessage{
        Text: &cleanedPayload["message"],
        Type: stringPtr("customer"),
    }

    var lastErr error
    maxRetries := 3

    for attempt := 0; attempt <= maxRetries; attempt++ {
        select {
        case <-ctx.Done():
            return fmt.Errorf("context cancelled during forward: %w", ctx.Err())
        default:
        }

        resp, httpResp, err := api.PostWebchatSessionMessages(ctx, sessionID, body)
        if err != nil {
            if httpResp != nil && httpResp.StatusCode == 429 {
                audit.Success = false
                audit.Error = "Rate limited (429)"
                wait := time.Duration(math.Pow(2, float64(attempt))) * time.Second
                fmt.Printf("Received 429. Retrying in %v...\n", wait)
                time.Sleep(wait)
                lastErr = err
                continue
            }
            audit.Success = false
            audit.Error = err.Error()
            return fmt.Errorf("API call failed: %w", err)
        }

        // Format verification
        if resp.Id == nil || *resp.Id == "" {
            audit.Success = false
            audit.Error = "Invalid response format: missing message ID"
            return fmt.Errorf("format verification failed: empty message ID")
        }

        audit.Success = true
        audit.Error = ""
        fmt.Printf("Message forwarded successfully. ID: %s\n", *resp.Id)
        return nil
    }

    return fmt.Errorf("max retries exceeded. Last error: %w", lastErr)
}

func stringPtr(s string) *string {
    return &s
}

Step 3: Processing Results with Latency Tracking, Audit Logging, and WAF Webhook Sync

You must track sanitization latency, calculate clean success rates, generate structured audit logs, and synchronize events with an external WAF engine via filtered webhooks.

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "io"
    "net/http"
    "sync"
    "time"
)

type SanitizationMetrics struct {
    mu                 sync.Mutex
    TotalRequests      int64
    SuccessfulCleans   int64
    TotalLatencyNs     int64
}

var metrics = &SanitizationMetrics{}

func RecordMetrics(audit SanitizationAudit) {
    metrics.mu.Lock()
    defer metrics.mu.Unlock()

    metrics.TotalRequests++
    if audit.Success {
        metrics.SuccessfulCleans++
    }
    metrics.TotalLatencyNs += int64(audit.SanitizationTime)
}

func GetSuccessRate() float64 {
    metrics.mu.Lock()
    defer metrics.mu.Unlock()
    if metrics.TotalRequests == 0 {
        return 0.0
    }
    return float64(metrics.SuccessfulCleans) / float64(metrics.TotalRequests) * 100.0
}

func GetAverageLatency() time.Duration {
    metrics.mu.Lock()
    defer metrics.mu.Unlock()
    if metrics.TotalRequests == 0 {
        return 0
    }
    return time.Duration(metrics.TotalLatencyNs / metrics.TotalRequests)
}

func SyncWithWAF(audit SanitizationAudit, webhookURL string) error {
    if webhookURL == "" {
        return nil
    }

    payload := map[string]interface{}{
        "event_type":      "input_sanitized",
        "timestamp":       audit.Timestamp.Format(time.RFC3339),
        "session_id":      audit.SessionID,
        "field":           audit.Field,
        "success":         audit.Success,
        "sanitization_ms": float64(audit.SanitizationTime.Milliseconds()),
    }

    jsonData, err := json.Marshal(payload)
    if err != nil {
        return fmt.Errorf("failed to marshal WAF payload: %w", err)
    }

    req, err := http.NewRequest("POST", webhookURL, bytes.NewBuffer(jsonData))
    if err != nil {
        return fmt.Errorf("failed to create WAF request: %w", err)
    }
    req.Header.Set("Content-Type", "application/json")

    client := &http.Client{Timeout: 5 * time.Second}
    resp, err := client.Do(req)
    if err != nil {
        return fmt.Errorf("WAF webhook delivery failed: %w", err)
    }
    defer resp.Body.Close()

    if resp.StatusCode < 200 || resp.StatusCode >= 300 {
        body, _ := io.ReadAll(resp.Body)
        return fmt.Errorf("WAF webhook returned %d: %s", resp.StatusCode, string(body))
    }

    return nil
}

Complete Working Example

The following script combines authentication, sanitization, forwarding, metrics, and webhook synchronization into a single runnable service. It exposes an HTTP endpoint for automated Genesys Cloud management.

package main

import (
    "context"
    "encoding/json"
    "fmt"
    "log/slog"
    "net/http"
    "os"
    "time"

    "github.com/mygenesys/genesyscloud-sdk-go/platform/webchat"
)

type RequestPayload struct {
    SessionID string            `json:"session_id"`
    Inputs    map[string]string `json:"inputs"`
}

func main() {
    api, err := initializeGenesysClient()
    if err != nil {
        slog.Error("Failed to initialize Genesys client", "error", err)
        os.Exit(1)
    }

    matrix := MessagingMatrix{
        Directive: CleanDirective{
            StripTags:       true,
            EncodeEntities:  true,
            MaxSanitizationTime: 2 * time.Second,
        },
        Rules: []InputRef{
            {FieldName: "message", MaxLength: 4096, AllowHTML: false},
            {FieldName: "subject", MaxLength: 256, AllowHTML: false},
        },
    }

    wafURL := os.Getenv("WAF_WEBHOOK_URL")

    http.HandleFunc("/sanitize-and-forward", func(w http.ResponseWriter, r *http.Request) {
        if r.Method != http.MethodPost {
            http.Error(w, "Method not allowed", http.StatusMethodNotAllowed)
            return
        }

        var req RequestPayload
        if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
            http.Error(w, "Invalid JSON", http.StatusBadRequest)
            return
        }

        start := time.Now()
        ctx := r.Context()

        cleaned, err := SanitizePayload(ctx, req.Inputs, matrix)
        sanitizationDuration := time.Since(start)

        audit := SanitizationAudit{
            Timestamp:        time.Now(),
            SessionID:        req.SessionID,
            Field:            "message",
            OriginalLength:   len(req.Inputs["message"]),
            CleanedLength:    len(cleaned["message"]),
            SanitizationTime: sanitizationDuration,
        }

        if err != nil {
            audit.Success = false
            audit.Error = err.Error()
            RecordMetrics(audit)
            slog.Warn("Sanitization failed", "error", err, "session", req.SessionID)
            http.Error(w, "Input validation failed", http.StatusBadRequest)
            return
        }

        err = ForwardToGenesys(ctx, api, req.SessionID, cleaned, &audit)
        RecordMetrics(audit)

        if err != nil {
            slog.Error("Forwarding failed", "error", err, "session", req.SessionID)
            http.Error(w, "Forwarding failed", http.StatusInternalServerError)
            return
        }

        // Sync with external WAF engine
        if wafErr := SyncWithWAF(audit, wafURL); wafErr != nil {
            slog.Warn("WAF sync failed", "error", wafErr)
        }

        w.Header().Set("Content-Type", "application/json")
        w.WriteHeader(http.StatusOK)
        json.NewEncoder(w).Encode(map[string]interface{}{
            "status":       "processed",
            "latency_ms":   sanitizationDuration.Milliseconds(),
            "success_rate": GetSuccessRate(),
            "avg_latency":  GetAverageLatency().String(),
        })
    })

    slog.Info("Sanitization gateway listening on :8080")
    if err := http.ListenAndServe(":8080", nil); err != nil {
        slog.Error("Server failed", "error", err)
    }
}

Common Errors & Debugging

Error: 401 Unauthorized

• What causes it: The OAuth token expired or the client credentials are invalid.
• How to fix it: Verify GENESYS_CLIENT_ID and GENESYS_CLIENT_SECRET match a configured OAuth client in Genesys Cloud. Ensure the client has webchat:session:read and webchat:session:write scopes assigned.
• Code showing the fix: The official SDK handles automatic refresh. If manual refresh is required, call config.GetAuthHelper().RefreshToken() before retrying.

Error: 429 Too Many Requests

• What causes it: Genesys Cloud rate limits are exceeded. Web Chat APIs enforce per-tenant and per-endpoint limits.
• How to fix it: Implement exponential backoff. The ForwardToGenesys function already includes retry logic with math.Pow(2, float64(attempt)) delays.
• Code showing the fix: See Step 2 retry loop. Adjust maxRetries or add jitter if cascading 429s occur across microservices.

Error: 400 Bad Request / Format Verification Failed

• What causes it: The sanitized payload violates Genesys Cloud schema constraints or contains unsupported characters after cleaning.
• How to fix it: Validate field lengths against the InputRef.MaxLength constraint before submission. Ensure HTML stripping does not leave unbalanced tags.
• Code showing the fix: The SanitizePayload function checks len(rawValue) > rule.MaxLength and returns early. Adjust MaxLength values to match your routing configuration.

Error: Context Deadline Exceeded

• What causes it: The sanitization pipeline exceeds maximum-sanitization-time limits, usually due to large payloads or complex Unicode normalization.
• How to fix it: Increase MaxSanitizationTime in CleanDirective or pre-filter payload size at the reverse proxy level.
• Code showing the fix: Modify matrix.Directive.MaxSanitizationTime = 5 * time.Second if legitimate messages require deeper inspection.

Official References

• Genesys Cloud Web Chat API Documentation
• Genesys Cloud Go SDK Reference
• OAuth 2.0 Client Credentials Grant
• Rate Limiting and Retry Guidelines