feat: support request headers as S3 object metadata in PUT templates

Add RequestHeaders (http.Header) to PutInput so that PUT metadata and
storage class templates can access incoming request headers via
.Input.RequestHeaders.Get. The lookup is case-insensitive, matching
Go's standard http.Header semantics. Multi-value headers can be accessed
with index and combined using sprig's join function.

Author: argos83

docs/configuration/example.md

@@ -397,6 +397,11 @@ targets:
     #       # Values can be templated. Empty values will be flushed.
     #       metadata:
     #         key: value
+    #         # Request headers can be forwarded as S3 object metadata using .Input.RequestHeaders.Get.
+    #         # The header lookup is case-insensitive
+    #         # (e.g. "x-my-header" and "X-My-Header" both work).
+    #         uploaded-by: '{{ .Input.RequestHeaders.Get "X-Uploaded-By" }}'
+    #         correlation-id: '{{ .Input.RequestHeaders.Get "X-Correlation-Id" }}'
     #       # System Metadata cases.
     #       # Values can be templated. Empty values will be flushed.
     #       systemMetadata:

docs/feature-guide/templates.md

@@ -298,12 +298,13 @@ These are the properties available:
 
 ### PutInput
 
-| Name        | Type    | Description                  |
-| ----------- | ------- | ---------------------------- |
-| RequestPath | String  | Request path                 |
-| Filename    | String  | Filename used for upload     |
-| ContentType | String  | File content type for upload |
-| ContentSize | Integer | File content size for upload |
+| Name           | Type              | Description                  |
+| -------------- | ----------------- | ---------------------------- |
+| RequestPath    | String            | Request path                 |
+| Filename       | String            | Filename used for upload     |
+| ContentType    | String            | File content type for upload |
+| ContentSize    | Integer           | File content size for upload |
+| RequestHeaders | [http.Header](https://golang.org/pkg/net/http/#Header) | Incoming request headers |
 
 ### PutData
 

pkg/s3-proxy/bucket/bucket-req-impl_test.go

@@ -1354,6 +1354,92 @@ func Test_requestContext_Put(t *testing.T) {
 				times: 1,
 			},
 		},
+		{
+			name: "should be ok to do templating on metadata using request headers",
+			fields: fields{
+				targetCfg: &config.TargetConfig{
+					Name:   "name",
+					Bucket: &config.BucketConfig{Prefix: "/"},
+					Actions: &config.ActionsConfig{
+						PUT: &config.PutActionConfig{
+							Config: &config.PutActionConfigConfig{
+								Metadata: map[string]string{
+									"first-header-value-only-key": `{{ .Input.RequestHeaders.Get "X-Custom-Header" }}`,
+									"all-header-values-key":       `{{ join "," (index .Input.RequestHeaders "X-Custom-Header") }}`,
+									"header-normalised-test-key":  `{{ .Input.RequestHeaders.Get "x-CASE-is-NORMALISED" }}`,
+								},
+								AllowOverride: true,
+							},
+						},
+					},
+				},
+				mountPath: "/mount",
+			},
+			args: args{
+				inp: &PutInput{
+					RequestPath: "/test",
+					Filename:    "file",
+					Body:        nil,
+					ContentType: "content-type",
+					RequestHeaders: func() http.Header {
+						h := http.Header{}
+						h["X-Custom-Header"] = []string{"first-value", "second-value"}
+						h["X-Case-Is-Normalised"] = []string{"test-value"}
+						return h
+					}(),
+				},
+			},
+			s3ClientHeadObjectMockResult: s3ClientHeadObjectMockResult{
+				times: 0,
+			},
+			s3ClientPutObjectMockResult: s3ClientPutObjectMockResult{
+				input2: &s3client.PutInput{
+					Key:         "/test/file",
+					ContentType: "content-type",
+					Metadata: map[string]string{
+						"first-header-value-only-key": "first-value",
+						"all-header-values-key":       "first-value,second-value",
+						"header-normalised-test-key":  "test-value",
+					},
+				},
+				res: &s3client.ResultInfo{
+					Bucket:     "bucket",
+					Key:        "key",
+					Region:     "region",
+					S3Endpoint: "s3endpoint",
+				},
+				times: 1,
+			},
+			webhookManagerManagePutHooksMockResult: webhookManagerManagePutHooksMockResult{
+				input2: "name",
+				input3: "/test",
+				input4: &webhook.PutInputMetadata{
+					Filename:    "file",
+					ContentType: "content-type",
+				},
+				input5: &webhook.S3Metadata{
+					Bucket:     "bucket",
+					Key:        "key",
+					Region:     "region",
+					S3Endpoint: "s3endpoint",
+				},
+				times: 1,
+			},
+			s3clManagerClientForTargetMockInput: "name",
+			responseHandlerPutMockResultTimes: responseHandlerPutMockResult{
+				input: &responsehandlermodels.PutInput{
+					Key:         "/test/file",
+					Filename:    "file",
+					ContentType: "content-type",
+					Metadata: map[string]string{
+						"first-header-value-only-key": "first-value",
+						"all-header-values-key":       "first-value,second-value",
+						"header-normalised-test-key":  "test-value",
+					},
+				},
+				times: 1,
+			},
+		},
 	}
 	for _, tt := range tests {
 		t.Run(tt.name, func(t *testing.T) {

pkg/s3-proxy/bucket/client.go

@@ -3,6 +3,7 @@ package bucket
 import (
 	"context"
 	"io"
+	"net/http"
 	"time"
 
 	"emperror.dev/errors"
@@ -44,11 +45,12 @@ type GetInput struct {
 
 // PutInput represents Put input.
 type PutInput struct {
-	RequestPath string
-	Filename    string
-	Body        io.ReadSeeker
-	ContentType string
-	ContentSize int64
+	RequestPath    string
+	Filename       string
+	Body           io.ReadSeeker
+	ContentType    string
+	ContentSize    int64
+	RequestHeaders http.Header
 }
 
 // PutData Put Data represents a put data structure used in put templates rendering.

pkg/s3-proxy/server/server.go

@@ -500,11 +500,12 @@ func (svr *Server) generateRouter() (http.Handler, error) {
 
 						// Create input for put request
 						inp := &bucket.PutInput{
-							RequestPath: requestPath,
-							Filename:    fileHeader.Filename,
-							Body:        file,
-							ContentType: fileHeader.Header.Get("Content-Type"),
-							ContentSize: fileHeader.Size,
+							RequestPath:    requestPath,
+							Filename:       fileHeader.Filename,
+							Body:           file,
+							ContentType:    fileHeader.Header.Get("Content-Type"),
+							ContentSize:    fileHeader.Size,
+							RequestHeaders: req.Header,
 						}
 						// Action
 						brctx.Put(req.Context(), inp)