1 files changed, 70 insertions, 0 deletions
diff --git a/pkg/util/filters.go b/pkg/util/filters.go
index bf16f89e3..51b2c5331 100644
--- a/pkg/util/filters.go
+++ b/pkg/util/filters.go
@@ -1,6 +1,10 @@
 package util
 
 import (
+	"encoding/json"
+	"fmt"
+	"net/http"
+	"strings"
 	"time"
 
 	"github.com/containers/podman/v3/pkg/timetype"
@@ -23,3 +27,69 @@ func ComputeUntilTimestamp(filter string, filterValues []string) (time.Time, err
 	}
 	return time.Unix(seconds, nanoseconds), nil
 }
+
+// filtersFromRequests extracts the "filters" parameter from the specified
+// http.Request.  The parameter can either be a `map[string][]string` as done
+// in new versions of Docker and libpod, or a `map[string]map[string]bool` as
+// done in older versions of Docker.  We have to do a bit of Yoga to support
+// both - just as Docker does as well.
+//
+// Please refer to https://github.com/containers/podman/issues/6899 for some
+// background.
+func FiltersFromRequest(r *http.Request) ([]string, error) {
+	var (
+		compatFilters map[string]map[string]bool
+		filters       map[string][]string
+		libpodFilters []string
+		raw           []byte
+	)
+
+	if _, found := r.URL.Query()["filters"]; found {
+		raw = []byte(r.Form.Get("filters"))
+	} else if _, found := r.URL.Query()["Filters"]; found {
+		raw = []byte(r.Form.Get("Filters"))
+	} else {
+		return []string{}, nil
+	}
+
+	// Backwards compat with older versions of Docker.
+	if err := json.Unmarshal(raw, &compatFilters); err == nil {
+		for filterKey, filterMap := range compatFilters {
+			for filterValue, toAdd := range filterMap {
+				if toAdd {
+					libpodFilters = append(libpodFilters, fmt.Sprintf("%s=%s", filterKey, filterValue))
+				}
+			}
+		}
+		return libpodFilters, nil
+	}
+
+	if err := json.Unmarshal(raw, &filters); err != nil {
+		return nil, err
+	}
+
+	for filterKey, filterSlice := range filters {
+		for _, filterValue := range filterSlice {
+			libpodFilters = append(libpodFilters, fmt.Sprintf("%s=%s", filterKey, filterValue))
+		}
+	}
+
+	return libpodFilters, nil
+}
+
+// PrepareFilters prepares a *map[string][]string of filters to be later searched
+// in lipod and compat API to get desired filters
+func PrepareFilters(r *http.Request) (*map[string][]string, error) {
+	filtersList, err := FiltersFromRequest(r)
+	if err != nil {
+		return nil, err
+	}
+	filterMap := map[string][]string{}
+	for _, filter := range filtersList {
+		split := strings.SplitN(filter, "=", 2)
+		if len(split) > 1 {
+			filterMap[split[0]] = append(filterMap[split[0]], split[1])
+		}
+	}
+	return &filterMap, nil
+}