feat: list users scim v2 endpoint (#9187)

# Which Problems Are Solved
- Adds support for the list users SCIM v2 endpoint

# How the Problems Are Solved
- Adds support for the list users SCIM v2 endpoints under `GET
/scim/v2/{orgID}/Users` and `POST /scim/v2/{orgID}/Users/.search`

# Additional Changes
- adds a new function `SearchUserMetadataForUsers` to the query layer to
query a metadata keyset for given user ids
- adds a new function `NewUserMetadataExistsQuery` to the query layer to
query a given metadata key value pair exists
- adds a new function `CountUsers` to the query layer to count users
without reading any rows
- handle `ErrorAlreadyExists` as scim errors `uniqueness`
- adds `NumberLessOrEqual` and `NumberGreaterOrEqual` query comparison
methods
- adds `BytesQuery` with `BytesEquals` and `BytesNotEquals` query
comparison methods

# Additional Context
Part of #8140
Supported fields for scim filters:
* `meta.created`
* `meta.lastModified`
* `id`
* `username`
* `name.familyName`
* `name.givenName`
* `emails` and `emails.value`
* `active` only eq and ne
* `externalId` only eq and ne

internal/api/http/parser.go

@@ -1,6 +1,7 @@
 package http
 
 import (
+	"errors"
 	"net/http"
 
 	"github.com/gorilla/schema"
@@ -26,3 +27,24 @@ func (p *Parser) Parse(r *http.Request, data interface{}) error {
 
 	return p.decoder.Decode(data, r.Form)
 }
+
+func (p *Parser) UnwrapParserError(err error) error {
+	if err == nil {
+		return nil
+	}
+
+	// try to unwrap the error
+	var multiErr schema.MultiError
+	if errors.As(err, &multiErr) && len(multiErr) == 1 {
+		for _, v := range multiErr {
+			var schemaErr schema.ConversionError
+			if errors.As(v, &schemaErr) {
+				return schemaErr.Err
+			}
+
+			return v
+		}
+	}
+
+	return err
+}

internal/api/http/parser_test.go

@@ -0,0 +1,81 @@
+package http
+
+import (
+	"bytes"
+	"errors"
+	"net/http"
+	"net/url"
+	"testing"
+
+	gschema "github.com/gorilla/schema"
+	"github.com/stretchr/testify/require"
+)
+
+type SampleSchema struct {
+	Value    *SampleSchemaValue `schema:"value"`
+	IntValue int                `schema:"intvalue"`
+}
+
+type SampleSchemaValue struct{}
+
+func (s *SampleSchemaValue) UnmarshalText(text []byte) error {
+	if string(text) == "foo" {
+		return nil
+	}
+
+	return errors.New("this is a test error")
+}
+
+func TestParser_UnwrapParserError(t *testing.T) {
+
+	tests := []struct {
+		name                 string
+		query                string
+		wantErr              bool
+		assertUnwrappedError func(err error, unwrappedErr error)
+	}{
+		{
+			name:    "unwrap ok",
+			query:   "value=test",
+			wantErr: true,
+			assertUnwrappedError: func(_, err error) {
+				require.Equal(t, "this is a test error", err.Error())
+			},
+		},
+		{
+			name:    "multiple errors",
+			query:   "value=test&intvalue=foo",
+			wantErr: true,
+			assertUnwrappedError: func(err error, unwrappedErr error) {
+				require.Equal(t, err, unwrappedErr)
+			},
+		},
+		{
+			name:  "no error",
+			query: "value=foo&intvalue=1",
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			p := NewParser()
+			encodedFormData := url.Values{}.Encode()
+			r, err := http.NewRequest(http.MethodPost, "http://exmaple.com?"+tt.query, bytes.NewBufferString(encodedFormData))
+			require.NoError(t, err)
+
+			data := new(SampleSchema)
+			err = p.Parse(r, data)
+			if !tt.wantErr {
+				require.NoError(t, err)
+				require.Nil(t, p.UnwrapParserError(err))
+				return
+			}
+
+			require.Error(t, err)
+			require.IsType(t, gschema.MultiError{}, err)
+
+			unwrappedErr := p.UnwrapParserError(err)
+			require.Error(t, unwrappedErr)
+			tt.assertUnwrappedError(err, unwrappedErr)
+		})
+	}
+}