Tag listing, fix potential deadlock if the response does not respect the page size.

lib/api_paginated_request.go

@@ -0,0 +1,108 @@
+package lib
+
+import (
+	"encoding/json"
+	"net/http"
+	"net/url"
+)
+
+type validatable interface {
+	validate() error
+}
+
+type paginatedRequestResponse interface {
+	setLastError(error)
+	close()
+}
+
+type paginatedRequestContext interface {
+	path() string
+	validateApiResponse(response *http.Response, initialRequest bool) error
+	processPartialResponse(response paginatedRequestResponse, apiResponse interface{})
+	createResponse(api *registryApi) paginatedRequestResponse
+	createJsonResponse() validatable
+}
+
+func (r *registryApi) executePaginatedRequest(ctx paginatedRequestContext, url *url.URL, initialRequest bool) (response *http.Response, close bool, err error) {
+	response, err = r.connector.Get(url)
+
+	if err != nil {
+		return
+	}
+
+	if err == nil {
+		close = response.Close
+		err = ctx.validateApiResponse(response, initialRequest)
+	}
+
+	return
+}
+
+func (r *registryApi) iteratePaginatedRequest(
+	ctx paginatedRequestContext,
+	lastApiResponse *http.Response,
+	response paginatedRequestResponse,
+) (
+	apiResponse *http.Response,
+	more bool,
+	err error,
+) {
+	requestUrl, err := r.paginatedRequestEndpointUrl(ctx.path(), lastApiResponse)
+
+	if err != nil {
+		return
+	}
+
+	apiResponse, needsClose, err := r.executePaginatedRequest(ctx, requestUrl, lastApiResponse == nil)
+
+	if needsClose {
+		defer apiResponse.Body.Close()
+	}
+
+	if err != nil {
+		return
+	}
+
+	more = apiResponse.Header.Get("link") != ""
+
+	jsonResponse := ctx.createJsonResponse()
+	decoder := json.NewDecoder(apiResponse.Body)
+	err = decoder.Decode(&jsonResponse)
+
+	if err != nil {
+		return
+	}
+
+	err = jsonResponse.validate()
+
+	if err != nil {
+		return
+	}
+
+	ctx.processPartialResponse(response, jsonResponse)
+
+	return
+}
+
+func (r *registryApi) paginatedRequest(ctx paginatedRequestContext) (response paginatedRequestResponse) {
+	response = ctx.createResponse(r)
+
+	go func() {
+		var apiResponse *http.Response
+		var err error
+		more := true
+
+		for more {
+			apiResponse, more, err = r.iteratePaginatedRequest(ctx, apiResponse, response)
+
+			if err != nil {
+				response.setLastError(err)
+				break
+			}
+		}
+
+		response.close()
+	}()
+
+	return
+}