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buffer.go
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buffer.go
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//go:generate stringer -type=BufferOption -output=./buffer_string.go
package eval
import (
"reflect"
"strings"
"github.com/hashicorp/hcl/v2"
"github.com/avenga/couper/config/body"
)
type BufferOption uint8
const (
BufferNone BufferOption = iota
BufferRequest
BufferResponse
)
func (i BufferOption) GoString() string {
var result []string
for _, o := range []BufferOption{BufferRequest, BufferResponse} {
if (i & o) == o {
result = append(result, o.String())
}
}
if len(result) == 0 {
return BufferNone.String()
}
return strings.Join(result, "|")
}
func (i BufferOption) Response() bool {
return i&BufferResponse == BufferResponse
}
// MustBuffer determines if any of the hcl.bodies makes use of 'body', 'form_body' or 'json_body' or
// of known attributes and variables which require a parsed client-request or backend-response body.
func MustBuffer(bodies ...hcl.Body) BufferOption {
result := BufferNone
if len(bodies) == 0 {
return result
}
var allExprs []hcl.Expression
allAttributes := body.CollectAttributes(bodies...)
allBlockTypes := body.CollectBlockTypes(bodies...)
for _, blockType := range allBlockTypes {
if opt := bufferWithBlock(blockType); opt != BufferNone {
result |= opt
}
}
// TODO: follow func call and their referenced remains
for _, attr := range allAttributes {
allExprs = append(allExprs, attr.Expr)
if opt := bufferWithAttribute(attr.Name); opt != BufferNone {
result |= opt
}
}
for _, expr := range allExprs {
for _, traversal := range expr.Variables() {
rootName := traversal.RootName()
if len(traversal) == 1 {
if rootName == ClientRequest || rootName == BackendRequest {
result |= BufferRequest
}
if rootName == BackendResponses || rootName == BackendResponse {
result |= BufferResponse
}
continue
}
if rootName != ClientRequest && rootName != BackendRequest && rootName != BackendResponses && rootName != BackendResponse {
continue
}
for _, t := range traversal[1:] {
nameField := reflect.ValueOf(t).FieldByName("Name")
name := nameField.String()
switch name {
case Body:
switch rootName {
case ClientRequest:
fallthrough
case BackendRequest:
result |= BufferRequest
case BackendResponse:
fallthrough
case BackendResponses:
result |= BufferResponse
}
case CTX: // e.g. jwt token (value) could be read from any (body) source
if rootName == ClientRequest || rootName == BackendRequest {
result |= BufferRequest
}
case FormBody:
if rootName == ClientRequest || rootName == BackendRequest {
result |= BufferRequest
}
case JsonBody:
switch rootName {
case ClientRequest:
fallthrough
case BackendRequest:
result |= BufferRequest
case BackendResponse:
fallthrough
case BackendResponses:
result |= BufferResponse
}
default:
// e.g. backend_responses.default
if len(traversal) == 2 {
if rootName == BackendResponse || rootName == BackendResponses {
result |= BufferResponse
}
}
}
}
}
}
return result
}
func bufferWithAttribute(attrName string) BufferOption {
switch attrName {
case attrAddFormParams, attrSetFormParams, attrDelFormParams:
return BufferRequest
}
return BufferNone
}
func bufferWithBlock(name string) BufferOption {
switch name {
case "openapi":
return BufferResponse
}
return BufferNone
}