91 lines
2.3 KiB
Go
91 lines
2.3 KiB
Go
package reqpreprocessor
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import (
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"bytes"
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"context"
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"encoding/json"
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"errors"
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"fmt"
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"io"
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"net/http"
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"github.com/beckn-one/beckn-onix/pkg/log"
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"github.com/beckn-one/beckn-onix/pkg/model"
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)
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// Config represents the configuration for the request preprocessor middleware.
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type Config struct {
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Role string
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ContextKeys []string
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}
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const contextKey = "context"
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// NewPreProcessor returns a middleware that processes the incoming request,
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// extracts the context field from the body, and adds relevant values (like subscriber ID).
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func NewPreProcessor(cfg *Config) (func(http.Handler) http.Handler, error) {
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if err := validateConfig(cfg); err != nil {
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return nil, err
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}
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return func(next http.Handler) http.Handler {
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return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
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body, err := io.ReadAll(r.Body)
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if err != nil {
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http.Error(w, "Failed to read request body", http.StatusBadRequest)
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return
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}
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var req map[string]interface{}
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ctx := r.Context()
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if err := json.Unmarshal(body, &req); err != nil {
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http.Error(w, "Failed to decode request body", http.StatusBadRequest)
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return
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}
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// Extract context from request.
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reqContext, ok := req["context"].(map[string]interface{})
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if !ok {
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http.Error(w, fmt.Sprintf("%s field not found or invalid.", contextKey), http.StatusBadRequest)
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return
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}
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var subID any
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switch cfg.Role {
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case "bap":
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subID = reqContext["bap_id"]
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case "bpp":
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subID = reqContext["bpp_id"]
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}
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if subID != nil {
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log.Debugf(ctx, "adding subscriberId to request:%s, %v", model.ContextKeySubscriberID, subID)
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ctx = context.WithValue(ctx, model.ContextKeySubscriberID, subID)
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}
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for _, key := range cfg.ContextKeys {
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ctxKey, _ := model.ParseContextKey(key)
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if v, ok := reqContext[key]; ok {
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ctx = context.WithValue(ctx, ctxKey, v)
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}
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}
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r.Body = io.NopCloser(bytes.NewBuffer(body))
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r.ContentLength = int64(len(body))
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r = r.WithContext(ctx)
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next.ServeHTTP(w, r)
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})
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}, nil
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}
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func validateConfig(cfg *Config) error {
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if cfg == nil {
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return errors.New("config cannot be nil")
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}
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if cfg.Role != "bap" && cfg.Role != "bpp" {
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return errors.New("role must be either 'bap' or 'bpp'")
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}
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for _, key := range cfg.ContextKeys {
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if _, err := model.ParseContextKey(key); err != nil {
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return err
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}
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}
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return nil
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}
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