func DropRule()

in webv2/api/rules.go [122:229]
105 lines of code
21 McCabe index (conditional complexity)

func DropRule(w http.ResponseWriter, r *http.Request) {
	ruleId := r.FormValue("id")
	if ruleId == "" {
		http.Error(w, fmt.Sprint("Rule id is empty"), http.StatusBadRequest)
		return
	}
	sessionState := session.GetSessionState()
	sessionState.Conv.ConvLock.Lock()
	defer sessionState.Conv.ConvLock.Unlock()
	conv := sessionState.Conv
	var rule internal.Rule
	position := -1

	for i, r := range conv.Rules {
		if r.Id == ruleId {
			rule = r
			position = i
			break
		}
	}
	if position == -1 {
		http.Error(w, fmt.Sprint("Rule to be deleted not found"), http.StatusBadRequest)
		return
	}

	if rule.Type == constants.AddIndex {
		if rule.Enabled {
			d, err := json.Marshal(rule.Data)
			if err != nil {
				http.Error(w, "Invalid rule data", http.StatusInternalServerError)
				return
			}
			var index ddl.CreateIndex
			err = json.Unmarshal(d, &index)
			if err != nil {
				http.Error(w, "Invalid rule data", http.StatusInternalServerError)
				return
			}
			tableId := index.TableId
			indexId := index.Id
			err = dropSecondaryIndexHelper(tableId, indexId)
			if err != nil {
				http.Error(w, fmt.Sprintf("%v", err), http.StatusBadRequest)
				return
			}
		}
	} else if rule.Type == constants.GlobalDataTypeChange {
		d, err := json.Marshal(rule.Data)
		if err != nil {
			http.Error(w, "Invalid rule data", http.StatusInternalServerError)
			return
		}
		typeMap := map[string]string{}
		err = json.Unmarshal(d, &typeMap)
		if err != nil {
			http.Error(w, "Invalid rule data", http.StatusInternalServerError)
			return
		}
		revertGlobalDataType(typeMap)
	} else if rule.Type == constants.EditColumnMaxLength {
		d, err := json.Marshal(rule.Data)
		if err != nil {
			http.Error(w, "Invalid rule data", http.StatusInternalServerError)
			return
		}
		var colMaxLength types.ColMaxLength
		err = json.Unmarshal(d, &colMaxLength)
		if err != nil {
			http.Error(w, "Invalid rule data", http.StatusInternalServerError)
			return
		}
		revertSpColMaxLength(colMaxLength, rule.AssociatedObjects)
	} else if rule.Type == constants.AddShardIdPrimaryKey {
		d, err := json.Marshal(rule.Data)
		if err != nil {
			http.Error(w, "Invalid rule data", http.StatusInternalServerError)
			return
		}
		var shardIdPrimaryKey types.ShardIdPrimaryKey
		err = json.Unmarshal(d, &shardIdPrimaryKey)
		if err != nil {
			http.Error(w, "Invalid rule data", http.StatusInternalServerError)
			return
		}
		tableName := checkInterleaving()
		if tableName != "" {
			http.Error(w, fmt.Sprintf("Rule cannot be deleted because some tables, eg: %v are interleaved. Please remove interleaving and try again.", tableName), http.StatusBadRequest)
			return
		}
		revertShardIdColumnAsPrimaryKey(shardIdPrimaryKey.AddedAtTheStart)
		removeShardIdColumnFromForeignKeys(shardIdPrimaryKey.AddedAtTheStart)
	} else {
		http.Error(w, "Invalid rule type", http.StatusInternalServerError)
		return
	}

	sessionState.Conv.Rules = append(conv.Rules[:position], conv.Rules[position+1:]...)
	if len(sessionState.Conv.Rules) == 0 {
		sessionState.Conv.Rules = nil
	}
	session.UpdateSessionFile()
	convm := session.ConvWithMetadata{
		SessionMetadata: sessionState.SessionMetadata,
		Conv:            *sessionState.Conv,
	}
	w.WriteHeader(http.StatusOK)
	json.NewEncoder(w).Encode(convm)
}