schema_registry.go

Documentation: github.com/qri-io/jsonschema

     1  package jsonschema
     2  
     3  import (
     4  	"context"
     5  	"fmt"
     6  	"strings"
     7  )
     8  
     9  var sr *SchemaRegistry
    10  
    11  // SchemaRegistry maintains a lookup table between schema string references
    12  // and actual schemas
    13  type SchemaRegistry struct {
    14  	schemaLookup  map[string]*Schema
    15  	contextLookup map[string]*Schema
    16  }
    17  
    18  // GetSchemaRegistry provides an accessor to a globally available schema registry
    19  func GetSchemaRegistry() *SchemaRegistry {
    20  	if sr == nil {
    21  		sr = &SchemaRegistry{
    22  			schemaLookup:  map[string]*Schema{},
    23  			contextLookup: map[string]*Schema{},
    24  		}
    25  	}
    26  	return sr
    27  }
    28  
    29  // ResetSchemaRegistry resets the main SchemaRegistry
    30  func ResetSchemaRegistry() {
    31  	sr = nil
    32  }
    33  
    34  // Get fetches a schema from the top level context registry or fetches it from a remote
    35  func (sr *SchemaRegistry) Get(ctx context.Context, uri string) *Schema {
    36  	uri = strings.TrimRight(uri, "#")
    37  	schema := sr.schemaLookup[uri]
    38  	if schema == nil {
    39  		fetchedSchema := &Schema{}
    40  		err := FetchSchema(ctx, uri, fetchedSchema)
    41  		if err != nil {
    42  			schemaDebug(fmt.Sprintf("[SchemaRegistry] Fetch error: %s", err.Error()))
    43  			return nil
    44  		}
    45  		if fetchedSchema == nil {
    46  			return nil
    47  		}
    48  		fetchedSchema.docPath = uri
    49  		// TODO(arqu): meta validate schema
    50  		schema = fetchedSchema
    51  		sr.schemaLookup[uri] = schema
    52  	}
    53  	return schema
    54  }
    55  
    56  // GetKnown fetches a schema from the top level context registry
    57  func (sr *SchemaRegistry) GetKnown(uri string) *Schema {
    58  	uri = strings.TrimRight(uri, "#")
    59  	return sr.schemaLookup[uri]
    60  }
    61  
    62  // GetLocal fetches a schema from the local context registry
    63  func (sr *SchemaRegistry) GetLocal(uri string) *Schema {
    64  	uri = strings.TrimRight(uri, "#")
    65  	return sr.contextLookup[uri]
    66  }
    67  
    68  // Register registers a schema to the top level context
    69  func (sr *SchemaRegistry) Register(sch *Schema) {
    70  	if sch.docPath == "" {
    71  		return
    72  	}
    73  	sr.schemaLookup[sch.docPath] = sch
    74  }
    75  
    76  // RegisterLocal registers a schema to a local context
    77  func (sr *SchemaRegistry) RegisterLocal(sch *Schema) {
    78  	if sch.id != "" && IsLocalSchemaID(sch.id) {
    79  		sr.contextLookup[sch.id] = sch
    80  	}
    81  
    82  	if sch.HasKeyword("$anchor") {
    83  		anchorKeyword := sch.keywords["$anchor"].(*Anchor)
    84  		anchorURI := sch.docPath + "#" + string(*anchorKeyword)
    85  		if sr.contextLookup == nil {
    86  			sr.contextLookup = map[string]*Schema{}
    87  		}
    88  		sr.contextLookup[anchorURI] = sch
    89  	}
    90  }
    91
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