Add custom parser

context.go

@@ -0,0 +1,28 @@
+package rzluramartian
+
+import "context"
+
+// NewContext returns a context wrapping the received parent
+func NewContext(parent context.Context) *Context {
+	return &Context{
+		Context: parent,
+	}
+}
+
+// Context provides information for a single request/response pair.
+type Context struct {
+	context.Context
+	skipRoundTrip bool
+}
+
+// SkipRoundTrip flags the context to skip the round trip
+func (c *Context) SkipRoundTrip() {
+	c.skipRoundTrip = true
+}
+
+// SkippingRoundTrip returns the flag for skipping the round trip
+func (c *Context) SkippingRoundTrip() bool {
+	return c.skipRoundTrip
+}
+
+var _ context.Context = &Context{Context: context.Background()}

go.mod

@@ -0,0 +1,8 @@
+module github.com/kyawmyintthein/rz-lura-martian
+
+go 1.13
+
+require (
+	github.com/google/martian v2.1.0+incompatible
+	github.com/luraproject/lura v1.4.1
+)

go.sum

@@ -0,0 +1,31 @@
+github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/devopsfaith/flatmap v0.0.0-20200601181759-8521186182fc h1:WM1VdC8LW8GIZUJuvXgQWm6LcZ8niL0D0WVuC3lKkQU=
+github.com/devopsfaith/flatmap v0.0.0-20200601181759-8521186182fc/go.mod h1:J9Y/58s7wx7HbHT3i4UKNwLGuBB9qCf0/JUdEFGDPmA=
+github.com/dimfeld/httptreemux v5.0.1+incompatible/go.mod h1:rbUlSV+CCpv/SuqUTP/8Bk2O3LyUV436/yaRGkhP6Z0=
+github.com/gin-contrib/sse v0.0.0-20170109093832-22d885f9ecc7/go.mod h1:VJ0WA2NBN22VlZ2dKZQPAPnyWw5XTlK1KymzLKsr59s=
+github.com/gin-gonic/gin v1.1.5-0.20170702092826-d459835d2b07/go.mod h1:7cKuhb5qV2ggCFctp2fJQ+ErvciLZrIeoOSOm6mUr7Y=
+github.com/go-chi/chi v4.0.1+incompatible/go.mod h1:eB3wogJHnLi3x/kFX2A+IbTBlXxmMeXJVKy9tTv1XzQ=
+github.com/golang/protobuf v1.0.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/google/martian v2.1.0+incompatible h1:/CP5g8u/VJHijgedC/Legn3BAbAaWPgecwXBIDzw5no=
+github.com/google/martian v2.1.0+incompatible/go.mod h1:9I4somxYTbIHy5NJKHRl3wXiIaQGbYVAs8BPL6v8lEs=
+github.com/gorilla/context v0.0.0-20160226214623-1ea25387ff6f/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
+github.com/gorilla/mux v1.6.1/go.mod h1:1lud6UwP+6orDFRuTfBEV8e9/aOM/c4fVVCaMa2zaAs=
+github.com/luraproject/lura v1.4.1 h1:zNzLYMzM13EaSrb9bfaPICD4bXtNqMCdyi42R1eBgro=
+github.com/luraproject/lura v1.4.1/go.mod h1:KIo1/+nsRZVxIO04Hkbth0GXSSzypvkFpF5KaIoLvlo=
+github.com/mattn/go-isatty v0.0.3/go.mod h1:M+lRXTBqGeGNdLjl/ufCoiOlB5xdOkqRJdNxMWT7Zi4=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=
+github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4=
+github.com/ugorji/go v0.0.0-20180112141927-9831f2c3ac10/go.mod h1:hnLbHMwcvSihnDhEfx2/BzKp2xb0Y+ErdfYcrs9tkJQ=
+github.com/urfave/negroni v0.3.0/go.mod h1:Meg73S6kFm/4PpbYdq35yYWoCZ9mS/YSx+lKnmiohz4=
+github.com/valyala/fastrand v1.0.0 h1:LUKT9aKer2dVQNUi3waewTbKV+7H17kvWFNKs2ObdkI=
+github.com/valyala/fastrand v1.0.0/go.mod h1:HWqCzkrkg6QXT8V2EXWvXCoow7vLwOFN002oeRzjapQ=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20190921015927-1a5e07d1ff72/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s=
+golang.org/x/sync v0.0.0-20190911185100-cd5d95a43a6e/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/go-playground/assert.v1 v1.2.1/go.mod h1:9RXL0bg/zibRAgZUYszZSwO/z8Y/a8bDuhia5mkpMnE=
+gopkg.in/go-playground/validator.v8 v8.18.2/go.mod h1:RX2a/7Ha8BgOhfk7j780h4/u/RRjR0eouCJSH80/M2Y=
+gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI=

header2body.go

@@ -0,0 +1,73 @@
+package rzluramartian
+
+import (
+	"bytes"
+	"encoding/json"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/google/martian/parse"
+)
+
+type (
+	HeaderModifierConfig struct {
+		KeysToExtract []string `json:"keys_to_extract"`
+	}
+
+	Header2BodyModifier struct {
+		keysToExtract []string
+	}
+)
+
+func headerModifierFromJSON(b []byte) (*parse.Result, error) {
+	cfg := &HeaderModifierConfig{}
+	if err := json.Unmarshal(b, cfg); err != nil {
+		return nil, err
+	}
+
+	mod := &Header2BodyModifier{
+		keysToExtract: cfg.KeysToExtract,
+	}
+	return parse.NewResult(mod, []parse.ModifierType{parse.Request})
+}
+
+func (m *Header2BodyModifier) ModifyRequest(req *http.Request) error {
+	var buf []byte
+	if req.Body != nil {
+		body, err := ioutil.ReadAll(req.Body)
+		if err != nil {
+			return err
+		}
+
+		data := make(map[string]interface{})
+		err = json.Unmarshal(body, &data)
+		if err != nil {
+			return err
+		}
+
+		for _, k := range m.keysToExtract {
+			data[k] = req.Header.Get(k)
+			req.Header.Del(k)
+		}
+
+		buf, err = json.Marshal(data)
+		if err != nil {
+			return err
+		}
+	} else {
+		data := make(map[string]interface{})
+		for _, k := range m.keysToExtract {
+			data[k] = req.Header.Get(k)
+			req.Header.Del(k)
+		}
+
+		var err error
+		buf, err = json.Marshal(data)
+		if err != nil {
+			return err
+		}
+	}
+	req.ContentLength = int64(len(buf))
+	req.Body = ioutil.NopCloser(bytes.NewBuffer(buf))
+	return nil
+}

martian.go

@@ -0,0 +1,164 @@
+package rzluramartian
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"errors"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/luraproject/lura/config"
+	"github.com/luraproject/lura/logging"
+	"github.com/luraproject/lura/proxy"
+	"github.com/luraproject/lura/transport/http/client"
+
+	// import the required martian packages so they can be used
+	"github.com/google/martian"
+	_ "github.com/google/martian/body"
+	_ "github.com/google/martian/cookie"
+	_ "github.com/google/martian/fifo"
+	_ "github.com/google/martian/header"
+	_ "github.com/google/martian/martianurl"
+	"github.com/google/martian/parse"
+	_ "github.com/google/martian/port"
+	_ "github.com/google/martian/priority"
+	_ "github.com/google/martian/stash"
+	_ "github.com/google/martian/status"
+)
+
+// NewBackendFactory creates a proxy.BackendFactory with the martian request executor wrapping the injected one.
+// If there is any problem parsing the extra config data, it just uses the injected request executor.
+func NewBackendFactory(logger logging.Logger, re client.HTTPRequestExecutor) proxy.BackendFactory {
+	return NewConfiguredBackendFactory(logger, func(_ *config.Backend) client.HTTPRequestExecutor { return re })
+}
+
+// NewConfiguredBackendFactory creates a proxy.BackendFactory with the martian request executor wrapping the injected one.
+// If there is any problem parsing the extra config data, it just uses the injected request executor.
+func NewConfiguredBackendFactory(logger logging.Logger, ref func(*config.Backend) client.HTTPRequestExecutor) proxy.BackendFactory {
+	parse.Register("static.Modifier", staticModifierFromJSON)
+	parse.Register("body.FromQueryString", queryModifierFromJSON)
+	parse.Register("body.FromHeader", headerModifierFromJSON)
+	return func(remote *config.Backend) proxy.Proxy {
+		re := ref(remote)
+		result, ok := ConfigGetter(remote.ExtraConfig).(Result)
+		if !ok {
+			return proxy.NewHTTPProxyWithHTTPExecutor(remote, re, remote.Decoder)
+		}
+		switch result.Err {
+		case nil:
+			return proxy.NewHTTPProxyWithHTTPExecutor(remote, HTTPRequestExecutor(result.Result, re), remote.Decoder)
+		case ErrEmptyValue:
+			return proxy.NewHTTPProxyWithHTTPExecutor(remote, re, remote.Decoder)
+		default:
+			logger.Error(result, remote.ExtraConfig)
+			return proxy.NewHTTPProxyWithHTTPExecutor(remote, re, remote.Decoder)
+		}
+	}
+}
+
+// HTTPRequestExecutor creates a wrapper over the received request executor, so the martian modifiers can be
+// executed before and after the execution of the request
+func HTTPRequestExecutor(result *parse.Result, re client.HTTPRequestExecutor) client.HTTPRequestExecutor {
+	return func(ctx context.Context, req *http.Request) (resp *http.Response, err error) {
+		if err = modifyRequest(result.RequestModifier(), req); err != nil {
+			return
+		}
+
+		mctx, ok := req.Context().(*Context)
+		if !ok || !mctx.SkippingRoundTrip() {
+			resp, err = re(ctx, req)
+			if err != nil {
+				return
+			}
+			if resp == nil {
+				err = ErrEmptyResponse
+				return
+			}
+		} else if resp == nil {
+			resp = &http.Response{
+				Request:    req,
+				Header:     http.Header{},
+				StatusCode: http.StatusOK,
+				Body:       ioutil.NopCloser(bytes.NewBufferString("")),
+			}
+		}
+
+		err = modifyResponse(result.ResponseModifier(), resp)
+		return
+	}
+}
+
+func modifyRequest(mod martian.RequestModifier, req *http.Request) error {
+	if req.Body == nil {
+		req.Body = ioutil.NopCloser(bytes.NewBufferString(""))
+	}
+	if req.Header == nil {
+		req.Header = http.Header{}
+	}
+
+	if mod == nil {
+		return nil
+	}
+	return mod.ModifyRequest(req)
+}
+
+func modifyResponse(mod martian.ResponseModifier, resp *http.Response) error {
+	if resp.Body == nil {
+		resp.Body = ioutil.NopCloser(bytes.NewBufferString(""))
+	}
+	if resp.Header == nil {
+		resp.Header = http.Header{}
+	}
+	if resp.StatusCode == 0 {
+		resp.StatusCode = http.StatusOK
+	}
+
+	if mod == nil {
+		return nil
+	}
+	return mod.ModifyResponse(resp)
+}
+
+// Namespace is the key to look for extra configuration details
+const Namespace = "github.com/kyawmyintthein/rz-martian"
+
+// Result is a simple wrapper over the parse.FromJSON response tuple
+type Result struct {
+	Result *parse.Result
+	Err    error
+}
+
+// ConfigGetter implements the config.ConfigGetter interface. It parses the extra config for the
+// martian adapter and returns a Result wrapping the results.
+func ConfigGetter(e config.ExtraConfig) interface{} {
+	cfg, ok := e[Namespace]
+	if !ok {
+		return Result{nil, ErrEmptyValue}
+	}
+
+	data, ok := cfg.(map[string]interface{})
+	if !ok {
+		return Result{nil, ErrBadValue}
+	}
+
+	raw, err := json.Marshal(data)
+	if err != nil {
+		return Result{nil, ErrMarshallingValue}
+	}
+
+	r, err := parse.FromJSON(raw)
+
+	return Result{r, err}
+}
+
+var (
+	// ErrEmptyValue is the error returned when there is no config under the namespace
+	ErrEmptyValue = errors.New("getting the extra config for the martian module")
+	// ErrBadValue is the error returned when the config is not a map
+	ErrBadValue = errors.New("casting the extra config for the martian module")
+	// ErrMarshallingValue is the error returned when the config map can not be marshalled again
+	ErrMarshallingValue = errors.New("marshalling the extra config for the martian module")
+	// ErrEmptyResponse is the error returned when the modifier receives a nil response
+	ErrEmptyResponse = errors.New("getting the http response from the request executor")
+)

querystring2body.go

@@ -0,0 +1,58 @@
+package rzluramartian
+
+import (
+	"bytes"
+	"encoding/json"
+	"html/template"
+	"io/ioutil"
+	"net/http"
+
+	"github.com/google/martian/parse"
+)
+
+type (
+	QueryModifierConfig struct {
+		KeysToExtract []string `json:"keys_to_extract"`
+		Template      string   `json:"template"`
+	}
+	Query2BodyModifier struct {
+		keysToExtract []string
+		template      *template.Template
+	}
+)
+
+func queryModifierFromJSON(b []byte) (*parse.Result, error) {
+	cfg := &QueryModifierConfig{}
+	if err := json.Unmarshal(b, cfg); err != nil {
+		return nil, err
+	}
+
+	tmpl, err := template.New("query2body_modifier").Parse(cfg.Template)
+	if err != nil {
+		return nil, err
+	}
+
+	mod := &Query2BodyModifier{
+		keysToExtract: cfg.KeysToExtract,
+		template:      tmpl,
+	}
+	return parse.NewResult(mod, []parse.ModifierType{parse.Request})
+}
+
+func (m *Query2BodyModifier) ModifyRequest(req *http.Request) error {
+	query := req.URL.Query()
+
+	buf := new(bytes.Buffer)
+	if err := m.template.Execute(buf, query); err != nil {
+		return err
+	}
+
+	for _, k := range m.keysToExtract {
+		query.Del(k)
+	}
+
+	req.ContentLength = int64(buf.Len())
+	req.Body = ioutil.NopCloser(buf)
+	req.URL.RawQuery = query.Encode()
+	return nil
+}