Initial QSfera import

Server/services/ocs/pkg/service/v0/response/response.go

@@ -0,0 +1,114 @@
+package response
+
+import (
+	"encoding/xml"
+	"net/http"
+	"reflect"
+
+	"github.com/go-chi/render"
+	"github.com/qsfera/server/services/ocs/pkg/service/v0/data"
+)
+
+// Response is the top level response structure
+type Response struct {
+	OCS *Payload `json:"ocs" xml:"ocs"`
+}
+
+var (
+	elementStartElement = xml.StartElement{Name: xml.Name{Local: "element"}}
+	metaStartElement    = xml.StartElement{Name: xml.Name{Local: "meta"}}
+	ocsName             = xml.Name{Local: "ocs"}
+	dataName            = xml.Name{Local: "data"}
+)
+
+// Payload combines response metadata and data
+type Payload struct {
+	Meta data.Meta `json:"meta" xml:"meta"`
+	Data any       `json:"data,omitempty" xml:"data,omitempty"`
+}
+
+// MarshalXML handles ocs specific wrapping of array members in 'element' tags for the data
+func (rsp Response) MarshalXML(e *xml.Encoder, start xml.StartElement) (err error) {
+	// first the easy part
+	// use ocs as the surrounding tag
+	start.Name = ocsName
+	if err = e.EncodeToken(start); err != nil {
+		return
+	}
+
+	// encode the meta tag
+	if err = e.EncodeElement(rsp.OCS.Meta, metaStartElement); err != nil {
+		return
+	}
+
+	// we need to use reflection to determine if p.Data is an array or a slice
+	rt := reflect.TypeOf(rsp.OCS.Data)
+	if rt != nil && (rt.Kind() == reflect.Array || rt.Kind() == reflect.Slice) {
+		// this is how to wrap the data elements in their own <element> tag
+		v := reflect.ValueOf(rsp.OCS.Data)
+		if err = e.EncodeToken(xml.StartElement{Name: dataName}); err != nil {
+			return
+		}
+		for i := 0; i < v.Len(); i++ {
+			if err = e.EncodeElement(v.Index(i).Interface(), elementStartElement); err != nil {
+				return
+			}
+		}
+		if err = e.EncodeToken(xml.EndElement{Name: dataName}); err != nil {
+			return
+		}
+	} else if err = e.EncodeElement(rsp.OCS.Data, xml.StartElement{Name: dataName}); err != nil {
+		return
+	}
+
+	// write the closing <ocs> tag
+	if err = e.EncodeToken(xml.EndElement{Name: start.Name}); err != nil {
+		return
+	}
+	return
+}
+
+// Render sets the status code of the http response, taking the ocs version into account
+func (rsp *Response) Render(w http.ResponseWriter, r *http.Request) error {
+	version := APIVersion(r.Context())
+	m := statusCodeMapper(version)
+	statusCode := m(rsp.OCS.Meta)
+	render.Status(r, statusCode)
+	if version == ocsVersion2 && statusCode == http.StatusOK {
+		rsp.OCS.Meta.StatusCode = statusCode
+	}
+	return nil
+}
+
+// DataRender creates an OK Payload for the given data
+func DataRender(d any) render.Renderer {
+	return &Response{
+		&Payload{
+			Meta: data.MetaOK,
+			Data: d,
+		},
+	}
+}
+
+// ErrRender creates an Error Payload with the given OCS error code and message
+// The httpcode will be determined using the API version stored in the context
+func ErrRender(c int, m string) render.Renderer {
+	return &Response{
+		&Payload{
+			Meta: data.Meta{Status: "error", StatusCode: c, Message: m},
+		},
+	}
+}
+
+func statusCodeMapper(version string) func(data.Meta) int {
+	var mapper func(data.Meta) int
+	switch version {
+	case ocsVersion1:
+		mapper = OcsV1StatusCodes
+	case ocsVersion2:
+		mapper = OcsV2StatusCodes
+	default:
+		mapper = defaultStatusCodeMapper
+	}
+	return mapper
+}

Server/services/ocs/pkg/service/v0/response/version.go

@@ -0,0 +1,92 @@
+package response
+
+import (
+	"context"
+	"net/http"
+
+	"github.com/go-chi/chi/v5"
+	"github.com/go-chi/render"
+	"github.com/qsfera/server/services/ocs/pkg/service/v0/data"
+)
+
+type key int
+
+const (
+	apiVersionKey key = iota
+	ocsVersion1       = "1"
+	ocsVersion2       = "2"
+)
+
+var (
+	defaultStatusCodeMapper = OcsV2StatusCodes
+)
+
+// APIVersion retrieves the api version from the context.
+func APIVersion(ctx context.Context) string {
+	value := ctx.Value(apiVersionKey)
+	if value != nil {
+		return value.(string)
+	}
+	return ""
+}
+
+// OcsV1StatusCodes returns the http status codes for the OCS API v1.
+func OcsV1StatusCodes(meta data.Meta) int {
+	if meta.StatusCode == data.MetaUnauthorized.StatusCode {
+		return http.StatusUnauthorized
+	}
+	return http.StatusOK
+}
+
+// OcsV2StatusCodes maps the OCS codes to http status codes for the ocs API v2.
+// see https://github.com/owncloud/core/blob/c08baf580927ecb8ec179028dda255fdd85b4568/lib/private/legacy/api.php#L528
+// also HTTP status codes for apps are the same as OCS codes
+// see https://github.com/owncloud/core/blob/b9ff4c93e051c94adfb301545098ae627e52ef76/lib/public/AppFramework/OCSController.php#L142-L150
+// I think this is a bug in the ocs v2 api, but since we are going to mimic bugs in КуСфера ... here goes
+func OcsV2StatusCodes(meta data.Meta) int {
+	sc := meta.StatusCode
+	switch sc {
+	case data.MetaNotFound.StatusCode:
+		return http.StatusNotFound
+	case data.MetaUnknownError.StatusCode:
+		fallthrough
+	case data.MetaServerError.StatusCode:
+		return http.StatusInternalServerError
+	case data.MetaUnauthorized.StatusCode:
+		return http.StatusUnauthorized
+	case data.MetaOK.StatusCode:
+		// TODO mustn't data.Meta be a pointer so this assignment has an effect
+		meta.StatusCode = http.StatusOK
+		return http.StatusOK
+	}
+	// any 2xx, 4xx and 5xx will be used as is
+	if sc >= 200 && sc < 600 {
+		return sc
+	}
+
+	// any error codes > 100 are treated as client errors
+	if sc > 100 && sc < 200 {
+		return http.StatusBadRequest
+	}
+
+	// TODO change this status code? yes, align with oc10 core mapStatusCodes
+	return http.StatusOK
+}
+
+// VersionCtx middleware is used to determine the response mapper from
+// the URL parameters passed through as the request. In case
+// the Version is unknown, we stop here and return a 404.
+func VersionCtx(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		version := chi.URLParam(r, "version")
+		if version == "" {
+			_ = render.Render(w, r, ErrRender(data.MetaBadRequest.StatusCode, "unknown ocs api version"))
+			return
+		}
+		w.Header().Set("Ocs-Api-Version", version)
+
+		// store version in context so handlers can access it
+		ctx := context.WithValue(r.Context(), apiVersionKey, version)
+		next.ServeHTTP(w, r.WithContext(ctx))
+	})
+}