Enable client side handling of the Auth info header

auth/auth.go

@@ -4,10 +4,15 @@
 package auth
 
 import (
+	"context"
 	"encoding/base64"
 	"encoding/json"
 	"net/http"
 
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/metadata"
+	"google.golang.org/grpc/status"
+
 	"github.com/Prabhjot-Sethi/core/errors"
 )
 
@@ -23,6 +28,9 @@ type AuthInfo struct {
 	SessionID string `json:"sid"`
 }
 
+// struct identifier for the context
+type authInfo struct{}
+
 // Sets Auth Info Header in the provided Http Request typically will
 // be used only by the entity that has performed that authentication
 // on the given http request already and has the relevant Auth Info
@@ -55,6 +63,59 @@ func GetAuthInfoHeader(r *http.Request) (*AuthInfo, error) {
 	return info, nil
 }
 
+// extract the header information from the GRPC context
+func extractHeader(ctx context.Context, header string) (string, error) {
+	md, ok := metadata.FromIncomingContext(ctx)
+	if !ok {
+		return "", status.Error(codes.NotFound, "No Metadata available in incoming message")
+	}
+
+	hValue, ok := md[header]
+	if !ok {
+		return "", status.Errorf(codes.NotFound, "missing header: %s", header)
+	}
+
+	if len(hValue) != 1 {
+		return "", status.Errorf(codes.NotFound, "no value associated with header: %s", header)
+	}
+
+	return hValue[0], nil
+}
+
+// Processes the headers available in context, to validate that the authentication is already performed
+func ProcessAuthInfo(ctx context.Context) (context.Context, error) {
+	val, err := extractHeader(ctx, httpClientAuthContext)
+	if err != nil {
+		return ctx, errors.Wrapf(errors.Unauthorized, "failed to extract auth info header: %s", err)
+	}
+
+	b, err := base64.RawURLEncoding.DecodeString(val)
+	if err != nil {
+		return ctx, errors.Wrapf(errors.Unauthorized, "invalid user info received: %s", err)
+	}
+
+	info := &AuthInfo{}
+	err = json.Unmarshal(b, info)
+	if err != nil {
+		return ctx, errors.Wrapf(errors.Unauthorized, "failed to get user info from header: %s", err)
+	}
+
+	// create new context with value of the auth info
+	authCtx := context.WithValue(ctx, authInfo{}, info)
+	return authCtx, nil
+}
+
+// gets Auth Info from Context available in the Http Request
+func GetAuthInfoFromContext(ctx context.Context) (*AuthInfo, error) {
+	val := ctx.Value(authInfo{})
+	switch info := val.(type) {
+	case *AuthInfo:
+		return info, nil
+	default:
+		return nil, errors.Wrapf(errors.NotFound, "auth info not found")
+	}
+}
+
 // delete the Auth info header from the given HTTP request
 func DeleteAuthInfoHeader(r *http.Request) {
 	r.Header.Del(httpClientAuthContext)

go.mod

@@ -2,7 +2,14 @@ module github.com/Prabhjot-Sethi/core
 
 go 1.24
 
-require github.com/google/go-cmp v0.7.0 // indirect
+require google.golang.org/grpc v1.72.1
+
+require (
+	github.com/google/go-cmp v0.7.0 // indirect
+	golang.org/x/sys v0.30.0 // indirect
+	google.golang.org/genproto/googleapis/rpc v0.0.0-20250218202821-56aae31c358a // indirect
+	google.golang.org/protobuf v1.36.5 // indirect
+)
 
 require (
 	github.com/golang/snappy v1.0.0 // indirect

go.sum

@@ -1,5 +1,7 @@
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/golang/protobuf v1.5.4 h1:i7eJL8qZTpSEXOPTxNKhASYpMn+8e5Q6AdndVa1dWek=
+github.com/golang/protobuf v1.5.4/go.mod h1:lnTiLA8Wa4RWRcIUkrtSVa5nRhsEGBg48fD6rSs7xps=
 github.com/golang/snappy v1.0.0 h1:Oy607GVXHs7RtbggtPBnr2RmDArIsAefDwvrdWvRhGs=
 github.com/golang/snappy v1.0.0/go.mod h1:/XxbfmMg8lxefKM7IXC3fBNl/7bRcc72aCRzEWrmP2Q=
 github.com/google/go-cmp v0.7.0 h1:wk8382ETsv4JYUZwIsn6YpYiWiBsYLSJiTsyBybVuN8=
@@ -27,6 +29,8 @@ golang.org/x/mod v0.6.0-dev.0.20220419223038-86c51ed26bb4/go.mod h1:jJ57K6gSWd91
 golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
 golang.org/x/net v0.0.0-20210226172049-e18ecbb05110/go.mod h1:m0MpNAwzfU5UDzcl9v0D8zg8gWTRqZa9RBIspLL5mdg=
 golang.org/x/net v0.0.0-20220722155237-a158d28d115b/go.mod h1:XRhObCWvk6IyKnWLug+ECip1KBveYUHfp+8e9klMJ9c=
+golang.org/x/net v0.35.0 h1:T5GQRQb2y08kTAByq9L4/bz8cipCdA8FbRTXewonqY8=
+golang.org/x/net v0.35.0/go.mod h1:EglIi67kWsHKlRzzVMUD93VMSWGFOMSZgxFjparz1Qk=
 golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.0.0-20220722155255-886fb9371eb4/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 golang.org/x/sync v0.11.0 h1:GGz8+XQP4FvTTrjZPzNKTMFtSXH80RAzG+5ghFPgK9w=
@@ -36,6 +40,8 @@ golang.org/x/sys v0.0.0-20201119102817-f84b799fce68/go.mod h1:h1NjWce9XRLGQEsW7w
 golang.org/x/sys v0.0.0-20210615035016-665e8c7367d1/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220520151302-bc2c85ada10a/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
 golang.org/x/sys v0.0.0-20220722155257-8c9f86f7a55f/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg=
+golang.org/x/sys v0.30.0 h1:QjkSwP/36a20jFYWkSue1YwXzLmsV5Gfq7Eiy72C1uc=
+golang.org/x/sys v0.30.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/term v0.0.0-20201126162022-7de9c90e9dd1/go.mod h1:bj7SfCRtBDWHUb9snDiAeCFNEtKQo2Wmx5Cou7ajbmo=
 golang.org/x/term v0.0.0-20210927222741-03fcf44c2211/go.mod h1:jbD1KX2456YbFQfuXm/mYQcufACuNUgVhRMnK/tPxf8=
 golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
@@ -48,3 +54,9 @@ golang.org/x/tools v0.0.0-20180917221912-90fa682c2a6e/go.mod h1:n7NCudcB/nEzxVGm
 golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo=
 golang.org/x/tools v0.1.12/go.mod h1:hNGJHUnrk76NpqgfD5Aqm5Crs+Hm0VOH/i9J2+nxYbc=
 golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20250218202821-56aae31c358a h1:51aaUVRocpvUOSQKM6Q7VuoaktNIaMCLuhZB6DKksq4=
+google.golang.org/genproto/googleapis/rpc v0.0.0-20250218202821-56aae31c358a/go.mod h1:uRxBH1mhmO8PGhU89cMcHaXKZqO+OfakD8QQO0oYwlQ=
+google.golang.org/grpc v1.72.1 h1:HR03wO6eyZ7lknl75XlxABNVLLFc2PAb6mHlYh756mA=
+google.golang.org/grpc v1.72.1/go.mod h1:wH5Aktxcg25y1I3w7H69nHfXdOG3UiadoBtjh3izSDM=
+google.golang.org/protobuf v1.36.5 h1:tPhr+woSbjfYvY6/GPufUoYizxw1cF/yFoxJ2fmpwlM=
+google.golang.org/protobuf v1.36.5/go.mod h1:9fA7Ob0pmnwhb644+1+CVWFRbNajQ6iRojtC/QF5bRE=