util.jsonschema: Library for JSON Schema validation

1 files changed, 327 insertions, 0 deletions

diff --git a/teal-src/util/jsonschema.tl b/teal-src/util/jsonschema.tl
new file mode 100644
index 00000000..1c11f63b
--- /dev/null
+++ b/teal-src/util/jsonschema.tl
@@ -0,0 +1,327 @@
+
+local record schema_t
+	enum type_e
+		"null"
+		"boolean"
+		"object"
+		"array"
+		"number"
+		"string"
+		"integer"
+	end
+
+	type : type_e
+	enum : { any }
+	const : any
+
+	allOf : { schema_t }
+	anyOf : { schema_t }
+	oneOf : { schema_t }
+
+	["not"] : schema_t
+	["if"] : schema_t
+	["then"] : schema_t
+	["else"] : schema_t
+
+	-- numbers
+	multipleOf : number
+	maximum : number
+	exclusiveMaximum : number
+	minimum : number
+	exclusiveMinimum : number
+
+	-- strings
+	maxLength : number
+	minLength : number
+	pattern : string
+	format : string
+
+	-- arrays
+	items : { schema_t } | schema_t
+	contains : { schema_t }
+	maxItems : number
+	minItems : number
+	uniqueItems : boolean
+	maxContains : number
+	minContains : number
+
+	-- objects
+	properties : { string : schema_t | type_e }
+	maxProperties : number
+	minProperties : number
+	required : { string }
+	dependentRequired : { string : { string } }
+	additionalProperties: schema_t
+	patternProperties: schema_t
+
+	-- xml
+	record xml_t
+		name : string
+		namespace : string
+		prefix : string
+		attribute : boolean
+		wrapped : boolean
+
+		-- nonstantard, maybe in the future
+		text : boolean
+	end
+
+	xml : xml_t
+
+	-- descriptive
+	title : string
+	description : string
+	deprecated : boolean
+	readOnly : boolean
+	writeOnly : boolean
+end
+local type_e = schema_t.type_e
+
+-- TODO validator function per schema property
+
+local type_validators : { type_e : function (schema_t, any) : boolean } = {}
+
+local function simple_validate(schema : type_e, data : any) : boolean
+	if schema == "object" and data is table then
+		return type(data) == "table" and (next(data)==nil or type((next(data, nil))) == "string")
+	elseif schema == "array" and data is table then
+		return type(data) == "table" and (next(data)==nil or type((next(data, nil))) == "number")
+	elseif schema == "integer" then
+		return math.type(data) == schema
+	else
+		return type(data) == schema
+	end
+end
+
+type_validators.string = function (schema : schema_t, data : any) : boolean
+	-- XXX this is measured in byte, while JSON measures in ... bork
+	-- TODO use utf8.len?
+	if data is string then
+		if schema.maxLength and #data > schema.maxLength then
+			return false
+		end
+		if schema.minLength and #data < schema.minLength then
+			return false
+		end
+		return true
+	end
+	return false
+end
+
+type_validators.number = function (schema : schema_t, data : number) : boolean
+	if schema.multipleOf and data % schema.multipleOf ~= 0 then
+		return false
+	end
+
+	if schema.maximum and not ( data <= schema.maximum ) then
+		return false
+	end
+
+	if schema.exclusiveMaximum and not ( data < schema.exclusiveMaximum ) then
+		return false
+	end
+
+	if schema.minimum and not ( data >= schema.minimum ) then
+		return false
+	end
+
+	if schema.exclusiveMinimum and not ( data > schema.exclusiveMinimum ) then
+		return false
+	end
+
+	return true
+end
+
+type_validators.integer = type_validators.number
+
+local function validate(schema : schema_t | type_e, data : any) : boolean
+	if schema is type_e then
+		return simple_validate(schema, data)
+	end
+	if schema is schema_t then
+		if schema.allOf then
+			for _, sub in ipairs(schema.allOf) do
+				if not validate(sub, data) then
+					return false
+				end
+			end
+			return true
+		end
+
+		if schema.oneOf then
+			local valid = 0
+			for _, sub in ipairs(schema.oneOf) do
+				if validate(sub, data) then
+					valid = valid + 1
+				end
+			end
+			return valid == 1
+		end
+
+		if schema.anyOf then
+			for _, sub in ipairs(schema.anyOf) do
+				if validate(sub, data) then
+					return true
+				end
+			end
+			return false
+		end
+
+		if schema["not"] then
+			if validate(schema["not"], data) then
+				return false
+			end
+		end
+
+		if schema["if"] then
+			if validate(schema["if"], data) then
+				if schema["then"] then
+					return validate(schema["then"], data)
+				end
+			else
+				if schema["else"] then
+					return validate(schema["else"], data)
+				end
+			end
+		end
+
+		if not simple_validate(schema.type, data) then
+			return false
+		end
+
+		if schema.const ~= nil and schema.const ~= data then
+			return false
+		end
+
+		if schema.enum ~= nil then
+			for _, v in ipairs(schema.enum) do
+				if v == data then
+					return true
+				end
+			end
+			return false
+		end
+
+		local validator = type_validators[schema.type]
+		if not validator then
+			return true
+		end
+
+		return validator(schema, data)
+	end
+end
+
+type_validators.table = function (schema : schema_t, data : any) : boolean
+	if data is table then
+
+		if schema.maxItems and #data > schema.maxItems then
+			return false
+		end
+
+		if schema.minItems and #data < schema.minItems then
+			return false
+		end
+
+		if schema.required then
+			for _, k in ipairs(schema.required) do
+				if data[k] == nil then
+					return false
+				end
+			end
+		end
+
+		if schema.properties then
+			for k, s in pairs(schema.properties) do
+				if data[k] ~= nil then
+					if not validate(s, data[k]) then
+						return false
+					end
+				end
+			end
+		end
+
+		if schema.additionalProperties then
+			for k, v in pairs(data) do
+				if k is string then
+					if not (schema.properties and schema.properties[k]) then
+						if not validate(schema.additionalProperties, v) then
+							return false
+						end
+					end
+				end
+			end
+		elseif schema.properties then
+			for k in pairs(data) do
+				if k is string then
+					if schema.properties[k] == nil then
+						return false
+					end
+				end
+			end
+		end
+
+		if schema.uniqueItems then
+			-- only works for scalars, would need to deep-compare for objects/arrays/tables
+			local values : { any : boolean } = {}
+			for _, v in pairs(data) do
+				if values[v] then
+					return false
+				end
+				values[v] = true
+			end
+			return true
+		end
+
+		local item_schemas = schema.items as {schema_t}
+		if item_schemas and item_schemas[1] == nil then
+			local item_schema = item_schemas as schema_t
+			for i, v in pairs(data) do
+				if i is number then
+					if not validate(item_schema, v) then
+						return false
+					end
+				end
+			end
+		elseif item_schemas and item_schemas[1] ~= nil then
+			for i, s in ipairs(item_schemas) do
+				validate(s, data[i])
+			end
+		end
+
+		return true
+	end
+	return false
+end
+
+type_validators.object = function (schema : schema_t, data : any) : boolean
+	if data is table then
+		for k in pairs(data) do
+			if not k is string then
+				return false
+			end
+		end
+
+		return type_validators.table(schema, data)
+	end
+	return false
+end
+
+type_validators.array = function (schema : schema_t, data : any) : boolean
+	if data is table then
+
+		-- just check that there the keys are all numbers
+		for i in pairs(data) do
+			if not i is number then
+				return false
+			end
+		end
+
+		return type_validators.table(schema, data)
+	end
+	return false
+end
+
+return {
+	validate = validate;
+	schema_t = schema_t;
+}