/
headerfilter.go
327 lines (294 loc) · 9.64 KB
/
headerfilter.go
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package builtin
import (
"fmt"
"strings"
"github.com/zalando/skipper/eskip"
"github.com/zalando/skipper/filters"
)
type headerType int
const (
setRequestHeader headerType = iota
appendRequestHeader
dropRequestHeader
setResponseHeader
appendResponseHeader
dropResponseHeader
setContextRequestHeader
appendContextRequestHeader
setContextResponseHeader
appendContextResponseHeader
copyRequestHeader
copyResponseHeader
copyRequestHeaderDeprecated
copyResponseHeaderDeprecated
depRequestHeader
depResponseHeader
)
const (
copyRequestHeaderDeprecatedName = "requestCopyHeader"
copyResponseHeaderDeprecatedName = "responseCopyHeader"
)
// common structure for requestHeader, responseHeader specifications and
// filters
type headerFilter struct {
typ headerType
key, value string
template *eskip.Template
}
// verifies that the filter config has two string parameters
func headerFilterConfig(typ headerType, config []interface{}) (string, string, *eskip.Template, error) {
switch typ {
case dropRequestHeader, dropResponseHeader:
if len(config) != 1 {
return "", "", nil, filters.ErrInvalidFilterParameters
}
default:
if len(config) != 2 {
return "", "", nil, filters.ErrInvalidFilterParameters
}
}
key, ok := config[0].(string)
if !ok {
return "", "", nil, filters.ErrInvalidFilterParameters
}
var value string
if len(config) == 2 {
value, ok = config[1].(string)
if !ok {
return "", "", nil, filters.ErrInvalidFilterParameters
}
}
switch typ {
case setRequestHeader, appendRequestHeader,
setResponseHeader, appendResponseHeader:
return key, "", eskip.NewTemplate(value), nil
default:
return key, value, nil, nil
}
}
// Deprecated: use setRequestHeader or appendRequestHeader
func NewRequestHeader() filters.Spec {
return &headerFilter{typ: depRequestHeader}
}
// Deprecated: use setRequestHeader or appendRequestHeader
func NewResponseHeader() filters.Spec {
return &headerFilter{typ: depResponseHeader}
}
// Returns a filter specification that is used to set headers for requests.
// Instances expect two parameters: the header name and the header value template,
// see eskip.Template.ApplyContext
// Name: "setRequestHeader".
//
// If the header name is 'Host', the filter uses the `SetOutgoingHost()`
// method to set the header in addition to the standard `Request.Header`
// map.
func NewSetRequestHeader() filters.Spec {
return &headerFilter{typ: setRequestHeader}
}
// Returns a filter specification that is used to append headers for requests.
// Instances expect two parameters: the header name and the header value template,
// see eskip.Template.ApplyContext
// Name: "appendRequestHeader".
//
// If the header name is 'Host', the filter uses the `SetOutgoingHost()`
// method to set the header in addition to the standard `Request.Header`
// map.
func NewAppendRequestHeader() filters.Spec {
return &headerFilter{typ: appendRequestHeader}
}
// Returns a filter specification that is used to delete headers for requests.
// Instances expect one parameter: the header name.
// Name: "dropRequestHeader".
func NewDropRequestHeader() filters.Spec {
return &headerFilter{typ: dropRequestHeader}
}
// Returns a filter specification that is used to set headers for responses.
// Instances expect two parameters: the header name and the header value template,
// see eskip.Template.ApplyContext
// Name: "setResponseHeader".
func NewSetResponseHeader() filters.Spec {
return &headerFilter{typ: setResponseHeader}
}
// Returns a filter specification that is used to append headers for responses.
// Instances expect two parameters: the header name and the header value template,
// see eskip.Template.ApplyContext
// Name: "appendResponseHeader".
func NewAppendResponseHeader() filters.Spec {
return &headerFilter{typ: appendResponseHeader}
}
// Returns a filter specification that is used to delete headers for responses.
// Instances expect one parameter: the header name.
// Name: "dropResponseHeader".
func NewDropResponseHeader() filters.Spec {
return &headerFilter{typ: dropResponseHeader}
}
// NewSetContextRequestHeader returns a filter specification used to set
// request headers with a given name and a value taken from the filter
// context state bag identified by its key.
func NewSetContextRequestHeader() filters.Spec {
return &headerFilter{typ: setContextRequestHeader}
}
// NewAppendContextRequestHeader returns a filter specification used to append
// request headers with a given name and a value taken from the filter
// context state bag identified by its key.
func NewAppendContextRequestHeader() filters.Spec {
return &headerFilter{typ: appendContextRequestHeader}
}
// NewSetContextResponseHeader returns a filter specification used to set
// response headers with a given name and a value taken from the filter
// context state bag identified by its key.
func NewSetContextResponseHeader() filters.Spec {
return &headerFilter{typ: setContextResponseHeader}
}
// NewAppendContextResponseHeader returns a filter specification used to append
// response headers with a given name and a value taken from the filter
// context state bag identified by its key.
func NewAppendContextResponseHeader() filters.Spec {
return &headerFilter{typ: appendContextResponseHeader}
}
// NewCopyRequestHeader creates a filter specification whose instances
// copies a specified source Header to a defined destination Header
// from the request to the proxy request.
func NewCopyRequestHeader() filters.Spec {
return &headerFilter{typ: copyRequestHeader}
}
// NewCopyResponseHeader creates a filter specification whose instances
// copies a specified source Header to a defined destination Header
// from the backend response to the proxy response.
func NewCopyResponseHeader() filters.Spec {
return &headerFilter{typ: copyResponseHeader}
}
func NewCopyRequestHeaderDeprecated() filters.Spec {
return &headerFilter{typ: copyRequestHeaderDeprecated}
}
func NewCopyResponseHeaderDeprecated() filters.Spec {
return &headerFilter{typ: copyResponseHeaderDeprecated}
}
func (spec *headerFilter) Name() string {
switch spec.typ {
case setRequestHeader:
return filters.SetRequestHeaderName
case appendRequestHeader:
return filters.AppendRequestHeaderName
case dropRequestHeader:
return filters.DropRequestHeaderName
case setResponseHeader:
return filters.SetResponseHeaderName
case appendResponseHeader:
return filters.AppendResponseHeaderName
case dropResponseHeader:
return filters.DropResponseHeaderName
case depRequestHeader:
return RequestHeaderName
case depResponseHeader:
return ResponseHeaderName
case setContextRequestHeader:
return filters.SetContextRequestHeaderName
case appendContextRequestHeader:
return filters.AppendContextRequestHeaderName
case setContextResponseHeader:
return filters.SetContextResponseHeaderName
case appendContextResponseHeader:
return filters.AppendContextResponseHeaderName
case copyRequestHeader:
return filters.CopyRequestHeaderName
case copyResponseHeader:
return filters.CopyResponseHeaderName
case copyRequestHeaderDeprecated:
return copyRequestHeaderDeprecatedName
case copyResponseHeaderDeprecated:
return copyResponseHeaderDeprecatedName
default:
panic("invalid header type")
}
}
//lint:ignore ST1016 "spec" makes sense here and we reuse the type for the filter
func (spec *headerFilter) CreateFilter(config []interface{}) (filters.Filter, error) {
key, value, template, err := headerFilterConfig(spec.typ, config)
return &headerFilter{typ: spec.typ, key: key, value: value, template: template}, err
}
func valueFromContext(
ctx filters.FilterContext,
headerName,
contextKey string,
isRequest bool,
apply func(string, string),
) {
contextValue, ok := ctx.StateBag()[contextKey]
if !ok {
return
}
stringValue := fmt.Sprint(contextValue)
apply(headerName, stringValue)
if isRequest && strings.ToLower(headerName) == "host" {
ctx.SetOutgoingHost(stringValue)
}
}
func (f *headerFilter) Request(ctx filters.FilterContext) {
header := ctx.Request().Header
switch f.typ {
case setRequestHeader:
value, ok := f.template.ApplyContext(ctx)
if ok {
header.Set(f.key, value)
if strings.ToLower(f.key) == "host" {
ctx.SetOutgoingHost(value)
}
}
case appendRequestHeader:
value, ok := f.template.ApplyContext(ctx)
if ok {
header.Add(f.key, value)
if strings.ToLower(f.key) == "host" {
ctx.SetOutgoingHost(value)
}
}
case depRequestHeader:
header.Add(f.key, f.value)
if strings.ToLower(f.key) == "host" {
ctx.SetOutgoingHost(f.value)
}
case dropRequestHeader:
header.Del(f.key)
case setContextRequestHeader:
valueFromContext(ctx, f.key, f.value, true, header.Set)
case appendContextRequestHeader:
valueFromContext(ctx, f.key, f.value, true, header.Add)
case copyRequestHeader, copyRequestHeaderDeprecated:
headerValue := header.Get(f.key)
if headerValue != "" {
header.Set(f.value, headerValue)
if strings.ToLower(f.value) == "host" {
ctx.SetOutgoingHost(headerValue)
}
}
}
}
func (f *headerFilter) Response(ctx filters.FilterContext) {
header := ctx.Response().Header
switch f.typ {
case setResponseHeader:
value, ok := f.template.ApplyContext(ctx)
if ok {
header.Set(f.key, value)
}
case appendResponseHeader:
value, ok := f.template.ApplyContext(ctx)
if ok {
header.Add(f.key, value)
}
case depResponseHeader:
header.Add(f.key, f.value)
case dropResponseHeader:
header.Del(f.key)
case setContextResponseHeader:
valueFromContext(ctx, f.key, f.value, false, header.Set)
case appendContextResponseHeader:
valueFromContext(ctx, f.key, f.value, false, header.Add)
case copyResponseHeader, copyResponseHeaderDeprecated:
headerValue := header.Get(f.key)
if headerValue != "" {
header.Set(f.value, headerValue)
}
}
}