Feat: 实现知识图谱数据库的检索方法，并对外提供接口
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@@ -0,0 +1,301 @@
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package services
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import (
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"context"
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"fmt"
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"github.com/neo4j/neo4j-go-driver/v5/neo4j"
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"knowledge-graph-backend/models"
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)
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type Neo4jService struct {
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driver neo4j.DriverWithContext
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}
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func NewNeo4jService(driver neo4j.DriverWithContext) *Neo4jService {
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return &Neo4jService{driver: driver}
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}
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func (s *Neo4jService) GetGraphData() models.GraphData {
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ctx := context.Background()
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var nodes []models.Node
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var edges []models.Edge
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nodeResult, err := neo4j.ExecuteQuery(ctx, s.driver,
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"MATCH (n) RETURN n",
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map[string]any{},
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neo4j.EagerResultTransformer,
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)
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if err != nil {
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fmt.Printf("Error querying nodes: %v\n", err)
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return models.GraphData{}
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}
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for _, record := range nodeResult.Records {
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if v, ok := record.Get("n"); ok {
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if n, ok := v.(neo4j.Node); ok {
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nodes = append(nodes, neo4jNodeToModel(n))
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}
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}
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}
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edgeResult, err := neo4j.ExecuteQuery(ctx, s.driver,
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"MATCH (a)-[r]->(b) RETURN a.id AS source, b.id AS target, r",
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map[string]any{},
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neo4j.EagerResultTransformer,
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)
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if err != nil {
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fmt.Printf("Error querying edges: %v\n", err)
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return models.GraphData{Nodes: nodes}
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}
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for _, record := range edgeResult.Records {
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source, _ := record.Get("source")
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target, _ := record.Get("target")
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v, _ := record.Get("r")
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if rel, ok := v.(neo4j.Relationship); ok {
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edge := neo4jRelToModel(rel)
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if s, ok := source.(string); ok {
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edge.Source = s
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}
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if t, ok := target.(string); ok {
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edge.Target = t
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}
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edges = append(edges, edge)
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}
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}
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return models.GraphData{Nodes: nodes, Edges: edges}
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}
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func (s *Neo4jService) GetNodeByID(id string) (models.Node, bool) {
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ctx := context.Background()
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result, err := neo4j.ExecuteQuery(ctx, s.driver,
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"MATCH (n {id: $id}) RETURN n",
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map[string]any{"id": id},
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neo4j.EagerResultTransformer,
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)
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if err != nil || len(result.Records) == 0 {
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return models.Node{}, false
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}
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v, _ := result.Records[0].Get("n")
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if n, ok := v.(neo4j.Node); ok {
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return neo4jNodeToModel(n), true
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}
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return models.Node{}, false
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}
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func (s *Neo4jService) SearchNodes(query string) []models.Node {
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if query == "" {
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return []models.Node{}
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}
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ctx := context.Background()
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result, err := neo4j.ExecuteQuery(ctx, s.driver,
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`MATCH (n)
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WHERE toLower(n.label) CONTAINS toLower($query)
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OR toLower(n.id) CONTAINS toLower($query)
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OR (n.type IS NOT NULL AND toLower(n.type) CONTAINS toLower($query))
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RETURN n`,
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map[string]any{"query": query},
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neo4j.EagerResultTransformer,
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)
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if err != nil {
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return []models.Node{}
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}
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var nodes []models.Node
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for _, record := range result.Records {
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v, _ := record.Get("n")
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if n, ok := v.(neo4j.Node); ok {
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nodes = append(nodes, neo4jNodeToModel(n))
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}
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}
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return nodes
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}
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func (s *Neo4jService) GetNeighbors(nodeID string) (models.NeighborResponse, bool) {
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ctx := context.Background()
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_, exists := s.GetNodeByID(nodeID)
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if !exists {
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return models.NeighborResponse{}, false
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}
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result, err := neo4j.ExecuteQuery(ctx, s.driver,
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`MATCH ({id: $id})-[r]-(m)
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RETURN m, r, startNode(r).id AS source, endNode(r).id AS target`,
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map[string]any{"id": nodeID},
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neo4j.EagerResultTransformer,
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)
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if err != nil {
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return models.NeighborResponse{Nodes: []models.Node{}, Edges: []models.Edge{}}, true
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}
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neighborMap := make(map[string]models.Node)
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edgeMap := make(map[string]models.Edge)
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for _, record := range result.Records {
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if v, ok := record.Get("m"); ok {
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if n, ok := v.(neo4j.Node); ok {
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modelNode := neo4jNodeToModel(n)
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neighborMap[modelNode.ID] = modelNode
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}
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}
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if v, ok := record.Get("r"); ok {
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if rel, ok := v.(neo4j.Relationship); ok {
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edge := neo4jRelToModel(rel)
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if source, ok := record.Get("source"); ok {
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if s, ok := source.(string); ok {
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edge.Source = s
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}
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}
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if target, ok := record.Get("target"); ok {
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if t, ok := target.(string); ok {
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edge.Target = t
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}
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}
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edgeMap[edge.ID] = edge
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}
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}
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}
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var neighborNodes []models.Node
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for _, n := range neighborMap {
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neighborNodes = append(neighborNodes, n)
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}
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var relatedEdges []models.Edge
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for _, e := range edgeMap {
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relatedEdges = append(relatedEdges, e)
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}
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return models.NeighborResponse{
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Nodes: neighborNodes,
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Edges: relatedEdges,
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}, true
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}
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func (s *Neo4jService) GetStats() map[string]int {
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ctx := context.Background()
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result, err := neo4j.ExecuteQuery(ctx, s.driver,
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`MATCH (n)
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RETURN count(n) AS totalNodes,
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sum(CASE WHEN n.type = '概念' THEN 1 ELSE 0 END) AS conceptNodes,
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sum(CASE WHEN n.type = '工具' THEN 1 ELSE 0 END) AS toolNodes,
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sum(CASE WHEN n.type = '应用' THEN 1 ELSE 0 END) AS applicationNodes`,
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map[string]any{},
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neo4j.EagerResultTransformer,
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)
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if err != nil || len(result.Records) == 0 {
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return map[string]int{}
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}
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record := result.Records[0]
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totalNodes := getInt(record, "totalNodes")
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conceptNodes := getInt(record, "conceptNodes")
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toolNodes := getInt(record, "toolNodes")
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applicationNodes := getInt(record, "applicationNodes")
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totalEdges := 0
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edgeResult, err := neo4j.ExecuteQuery(ctx, s.driver,
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"MATCH ()-[r]->() RETURN count(r) AS totalEdges",
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map[string]any{},
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neo4j.EagerResultTransformer,
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)
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if err == nil && len(edgeResult.Records) > 0 {
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totalEdges = getInt(edgeResult.Records[0], "totalEdges")
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}
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return map[string]int{
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"totalNodes": totalNodes,
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"totalEdges": totalEdges,
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"conceptNodes": conceptNodes,
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"toolNodes": toolNodes,
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"applicationNodes": applicationNodes,
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}
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}
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func neo4jNodeToModel(n neo4j.Node) models.Node {
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props := n.Props
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node := models.Node{
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ID: getStr(props, "id"),
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Label: getStr(props, "label"),
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Type: getStr(props, "type"),
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Properties: make(map[string]interface{}),
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}
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if v, ok := props["x"]; ok && v != nil {
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node.X = getFloat64(v)
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}
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if v, ok := props["y"]; ok && v != nil {
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node.Y = getFloat64(v)
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}
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if v, ok := props["style"]; ok && v != nil {
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if s, ok := v.(map[string]interface{}); ok {
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node.Style = s
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}
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}
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for k, v := range props {
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switch k {
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case "id", "label", "type", "x", "y", "style":
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default:
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node.Properties[k] = v
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}
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}
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return node
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}
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func neo4jRelToModel(r neo4j.Relationship) models.Edge {
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props := r.Props
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edge := models.Edge{
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ID: getStr(props, "id"),
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Label: getStr(props, "label"),
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Type: r.Type,
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Properties: make(map[string]interface{}),
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}
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if v, ok := props["style"]; ok && v != nil {
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if s, ok := v.(map[string]interface{}); ok {
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edge.Style = s
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}
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}
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for k, v := range props {
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switch k {
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case "id", "label", "style":
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default:
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edge.Properties[k] = v
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}
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}
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return edge
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}
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func getStr(props map[string]any, key string) string {
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if v, ok := props[key]; ok && v != nil {
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if s, ok := v.(string); ok {
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return s
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}
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}
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return ""
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}
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func getFloat64(v any) float64 {
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switch val := v.(type) {
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case float64:
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return val
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case int64:
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return float64(val)
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case int:
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return float64(val)
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}
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return 0
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}
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func getInt(record *neo4j.Record, key string) int {
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v, _ := record.Get(key)
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switch val := v.(type) {
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case int64:
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return int(val)
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case int:
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return val
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case float64:
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return int(val)
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}
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return 0
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}
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