feat: support for list size validation for server plugins based (#103)

fixes #76

Author: velias

README.md

@@ -273,6 +273,16 @@ Ensure value is less than
 ```@constraint(multipleOf: 10)```
 Ensure value is a multiple
 
+### Array/List
+
+#### minItems
+```@constraint(minItems: 3)```
+Restrict array/List to a minimum length
+
+#### maxItems
+```@constraint(maxItems: 3)```
+Restrict array/List to a maximum length
+
 ### ConstraintDirectiveError
 Each validation error throws a `ConstraintDirectiveError`. Combined with a formatError function, this can be used to customise error messages.
 

lib/query-validation-visitor.js

@@ -116,9 +116,6 @@ module.exports = class QueryValidationVisitor {
     const argTypeDef = this.currentrFieldDef.args.find(d => d.name === argName)
     const value = valueFromAST(arg.value, argTypeDef.type, this.variableValues)
 
-    // nothing to validate
-    if (!value) return
-
     let variableName
 
     if (arg.value.kind === Kind.VARIABLE) variableName = arg.value.name.value
@@ -128,12 +125,18 @@ module.exports = class QueryValidationVisitor {
     if (isNonNullType(valueTypeDef)) valueTypeDef = valueTypeDef.ofType
 
     if (isInputObjectType(valueTypeDef)) {
+      // nothing to validate
+      if (!value) return
+
       const inputObjectTypeDef = getNamedType(valueTypeDef)
 
       validateInputTypeValue(this.context, inputObjectTypeDef, argName, variableName, value, this.currentField, variableName)
     } else if (isListType(valueTypeDef)) {
       validateArrayTypeValue(this.context, valueTypeDef, argTypeDef, value, this.currentField, argName, variableName, variableName)
     } else {
+      // nothing to validate
+      if (!value) return
+
       const fieldNameForError = variableName || this.currentField.name.value + '.' + argName
 
       validateScalarTypeValue(this.context, this.currentField, argTypeDef, valueTypeDef, value, variableName, argName, fieldNameForError, '')
@@ -177,17 +180,44 @@ function validateArrayTypeValue (context, valueTypeDef, typeDefWithDirective, va
 
   if (isNonNullType(valueTypeDefArray)) valueTypeDefArray = valueTypeDefArray.ofType
 
-  value.forEach((element, index) => {
-    const iFieldNameFullIndexed = iFieldNameFull ? `${iFieldNameFull}[${index++}]` : `[${index++}]`
+  // Validate array/list size
+  const directiveArgumentMap = getDirectiveValues(constraintDirectiveTypeDefsObj, typeDefWithDirective.astNode)
+
+  if (directiveArgumentMap) {
+    let errMessageBase
 
-    if (isInputObjectType(valueTypeDefArray)) {
-      validateInputTypeValue(context, valueTypeDefArray, argName, variableName, element, currentField, iFieldNameFullIndexed)
+    if (variableName) {
+      errMessageBase = `Variable "$${variableName}" at "${iFieldNameFull}" `
     } else {
-      const atMessage = ` at "${iFieldNameFullIndexed}"`
+      errMessageBase = `Argument "${argName}" of "${currentField.name.value}" `
+    }
 
-      validateScalarTypeValue(context, currentField, typeDefWithDirective, valueTypeDef, element, variableName, argName, iFieldNameFullIndexed, atMessage)
+    if (directiveArgumentMap.minItems && (!value || value.length < directiveArgumentMap.minItems)) {
+      context.reportError(new ValidationError(iFieldNameFull,
+        errMessageBase + `must be at least ${directiveArgumentMap.minItems} in length`,
+        [{ arg: 'minItems', value: directiveArgumentMap.minItems }]))
+    }
+    if (directiveArgumentMap.maxItems && value && value.length > directiveArgumentMap.maxItems) {
+      context.reportError(new ValidationError(iFieldNameFull,
+        errMessageBase + `must be no more than ${directiveArgumentMap.maxItems} in length`,
+        [{ arg: 'maxItems', value: directiveArgumentMap.maxItems }]))
     }
-  })
+  }
+
+  // Validate array content
+  if (value) {
+    value.forEach((element, index) => {
+      const iFieldNameFullIndexed = iFieldNameFull ? `${iFieldNameFull}[${index++}]` : `[${index++}]`
+
+      if (isInputObjectType(valueTypeDefArray)) {
+        validateInputTypeValue(context, valueTypeDefArray, argName, variableName, element, currentField, iFieldNameFullIndexed)
+      } else {
+        const atMessage = ` at "${iFieldNameFullIndexed}"`
+
+        validateScalarTypeValue(context, currentField, typeDefWithDirective, valueTypeDef, element, variableName, argName, iFieldNameFullIndexed, atMessage)
+      }
+    })
+  }
 }
 
 class InputObjectValidationVisitor {
@@ -213,20 +243,24 @@ class InputObjectValidationVisitor {
     const iFieldNameFull = (this.parentNames ? this.parentNames + '.' + iFieldName : iFieldName)
     const value = this.value[iFieldName]
 
-    if (value) {
-      let valueTypeAst = node.type
+    let valueTypeAst = node.type
 
-      if (valueTypeAst.kind === Kind.NON_NULL_TYPE) { valueTypeAst = valueTypeAst.type }
+    if (valueTypeAst.kind === Kind.NON_NULL_TYPE) { valueTypeAst = valueTypeAst.type }
 
-      const valueTypeDef = typeFromAST(this.context.getSchema(), valueTypeAst)
+    const valueTypeDef = typeFromAST(this.context.getSchema(), valueTypeAst)
 
-      if (isInputObjectType(valueTypeDef)) {
-        validateInputTypeValue(this.context, valueTypeDef, this.argName, this.variableName, value, this.currentField, iFieldNameFull)
-      } else if (isListType(valueTypeDef)) {
-        validateArrayTypeValue(this.context, valueTypeDef, iFieldTypeDef, value, this.currentField, this.argName, this.variableName, iFieldNameFull)
-      } else {
-        validateScalarTypeValue(this.context, this.currentField, iFieldTypeDef, valueTypeDef, value, this.variableName, this.argName, iFieldNameFull, ` at "${iFieldNameFull}"`)
-      }
+    if (isInputObjectType(valueTypeDef)) {
+      // nothing to validate
+      if (!value) return
+
+      validateInputTypeValue(this.context, valueTypeDef, this.argName, this.variableName, value, this.currentField, iFieldNameFull)
+    } else if (isListType(valueTypeDef)) {
+      validateArrayTypeValue(this.context, valueTypeDef, iFieldTypeDef, value, this.currentField, this.argName, this.variableName, iFieldNameFull)
+    } else {
+      // nothing to validate
+      if (!value) return
+
+      validateScalarTypeValue(this.context, this.currentField, iFieldTypeDef, valueTypeDef, value, this.variableName, this.argName, iFieldNameFull, ` at "${iFieldNameFull}"`)
     }
   }
 }

lib/type-defs.js

@@ -24,7 +24,14 @@ const constraintDirectiveTypeDefs = /* GraphQL */`
     exclusiveMin: Float
     exclusiveMax: Float
     multipleOf: Float
+
+    # Array/List size constraints
+    minItems: Int
+    maxItems: Int
+
+    # Shared for Schema wrapper
     uniqueTypeName: String
+
   ) on INPUT_FIELD_DEFINITION | FIELD_DEFINITION | ARGUMENT_DEFINITION`
 
 const constraintDirectiveTypeDefsObj = new GraphQLDirective({
@@ -75,7 +82,15 @@ const constraintDirectiveTypeDefsObj = new GraphQLDirective({
       type: GraphQLFloat
     },
 
-    // Shared
+    // Array/List size constraints
+    minItems: {
+      type: GraphQLInt
+    },
+    maxItems: {
+      type: GraphQLInt
+    },
+
+    // Shared for Schema wrapper
     uniqueTypeName: {
       type: GraphQLString
     }