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package validation |
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import ( |
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"bytes" |
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"encoding/json" |
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"errors" |
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"fmt" |
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"strings" |
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"golang.org/x/text/language" |
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) |
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// Violation is the abstraction for validator errors. You can use your own implementations on the application |
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// side to use it for your needs. In order for the validator to generate application violations, |
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// it is necessary to implement the ViolationFactory interface and inject it into the validator. |
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// You can do this by using the SetViolationFactory option in the NewValidator constructor. |
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type Violation interface { |
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error |
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// Code is unique, short, and semantic string that can be used to programmatically |
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// test for specific violation. All "code" values are defined in the "github.com/muonsoft/validation/code" package |
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// and are protected by backward compatibility rules. |
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Code() string |
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// Is can be used to check that the violation contains one of the specific codes. |
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// For an empty list, it should always returns false. |
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Is(codes ...string) bool |
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// Message is a translated message with injected values from constraint. It can be used to show |
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// a description of a violation to the end-user. Possible values for build-in constraints |
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// are defined in the "github.com/muonsoft/validation/message" package and can be changed at any time, |
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// even in patch versions. |
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Message() string |
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// MessageTemplate is a template for rendering message. Alongside parameters it can be used to |
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// render the message on the client-side of the library. |
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MessageTemplate() string |
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// Parameters is the map of the template variables and their values provided by the specific constraint. |
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Parameters() []TemplateParameter |
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// PropertyPath is a path that points to the violated property. |
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// See PropertyPath type description for more info. |
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PropertyPath() *PropertyPath |
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} |
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// ViolationFactory is the abstraction that can be used to create custom violations on the application side. |
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// Use the SetViolationFactory option on the NewValidator constructor to inject your own factory into the validator. |
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type ViolationFactory interface { |
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// CreateViolation creates a new instance of Violation. |
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CreateViolation( |
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code, |
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messageTemplate string, |
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pluralCount int, |
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parameters []TemplateParameter, |
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propertyPath *PropertyPath, |
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lang language.Tag, |
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) Violation |
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} |
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// NewViolationFunc is an adapter that allows you to use ordinary functions as a ViolationFactory. |
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type NewViolationFunc func( |
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code, |
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messageTemplate string, |
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pluralCount int, |
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parameters []TemplateParameter, |
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propertyPath *PropertyPath, |
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lang language.Tag, |
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) Violation |
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// CreateViolation creates a new instance of a Violation. |
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func (f NewViolationFunc) CreateViolation( |
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code, |
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messageTemplate string, |
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pluralCount int, |
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parameters []TemplateParameter, |
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propertyPath *PropertyPath, |
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lang language.Tag, |
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) Violation { |
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return f(code, messageTemplate, pluralCount, parameters, propertyPath, lang) |
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} |
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// ViolationList is a linked list of violations. It is the usual type of error that is returned from a validator. |
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type ViolationList struct { |
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len int |
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first *ViolationListElement |
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last *ViolationListElement |
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} |
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// ViolationListElement points to violation build by validator. It also implements |
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// Violation and can be used as a proxy to underlying violation. |
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type ViolationListElement struct { |
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next *ViolationListElement |
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violation Violation |
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} |
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// NewViolationList creates a new ViolationList, that can be immediately populated with |
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// variadic arguments of violations. |
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func NewViolationList(violations ...Violation) *ViolationList { |
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list := &ViolationList{} |
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list.Append(violations...) |
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return list |
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} |
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// Len returns length of the linked list. |
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func (list *ViolationList) Len() int { |
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return list.len |
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} |
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// First returns the first element of the linked list. |
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func (list *ViolationList) First() *ViolationListElement { |
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return list.first |
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} |
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// Last returns the last element of the linked list. |
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func (list *ViolationList) Last() *ViolationListElement { |
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return list.last |
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} |
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// Append appends violations to the end of the linked list. |
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func (list *ViolationList) Append(violations ...Violation) { |
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for i := range violations { |
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element := &ViolationListElement{violation: violations[i]} |
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if list.first == nil { |
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list.first = element |
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list.last = element |
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} else { |
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list.last.next = element |
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list.last = element |
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} |
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} |
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list.len += len(violations) |
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} |
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// Join is used to append the given violation list to the end of the current list. |
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func (list *ViolationList) Join(violations *ViolationList) { |
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if violations == nil || violations.len == 0 { |
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return |
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} |
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if list.first == nil { |
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list.first = violations.first |
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list.last = violations.last |
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} else { |
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list.last.next = violations.first |
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list.last = violations.last |
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} |
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list.len += violations.len |
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} |
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// Error returns a formatted list of errors as a string. |
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func (list *ViolationList) Error() string { |
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if list.len == 0 { |
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return "the list of violations is empty, it looks like you forgot to use the AsError method somewhere" |
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} |
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var s strings.Builder |
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s.Grow(32 * list.len) |
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i := 0 |
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for e := list.first; e != nil; e = e.next { |
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v := e.violation |
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if i > 0 { |
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s.WriteString("; ") |
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} |
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if iv, ok := v.(*internalViolation); ok { |
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iv.writeToBuilder(&s) |
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} else { |
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s.WriteString(v.Error()) |
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} |
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i++ |
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} |
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return s.String() |
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} |
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// AppendFromError appends a single violation or a slice of violations into the end of a given slice. |
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// If an error does not implement the Violation or ViolationList interface, it will return an error itself. |
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// Otherwise nil will be returned. |
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func (list *ViolationList) AppendFromError(err error) error { |
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if violation, ok := UnwrapViolation(err); ok { |
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list.Append(violation) |
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} else if violationList, ok := UnwrapViolationList(err); ok { |
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list.Join(violationList) |
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} else if err != nil { |
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return err |
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} |
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return nil |
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} |
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// Has can be used to check that at least one of the violations contains one of the specific codes. |
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// For an empty list of codes, it should always returns false. |
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func (list *ViolationList) Has(codes ...string) bool { |
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for e := list.first; e != nil; e = e.next { |
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if e.violation.Is(codes...) { |
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return true |
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} |
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} |
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return false |
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} |
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// Filter returns a new list of violations with violations of given codes. |
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func (list *ViolationList) Filter(codes ...string) *ViolationList { |
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filtered := &ViolationList{} |
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for e := list.first; e != nil; e = e.next { |
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if e.violation.Is(codes...) { |
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filtered.Append(e.violation) |
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} |
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} |
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return filtered |
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} |
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// AsError converts the list of violations to an error. This method correctly handles cases where |
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// the list of violations is empty. It returns nil on an empty list, indicating that the validation was successful. |
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func (list *ViolationList) AsError() error { |
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if list.len == 0 { |
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return nil |
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} |
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return list |
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} |
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// AsSlice converts underlying linked list into slice of Violation. |
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func (list *ViolationList) AsSlice() []Violation { |
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violations := make([]Violation, list.len) |
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i := 0 |
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for e := list.first; e != nil; e = e.next { |
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violations[i] = e.violation |
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i++ |
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} |
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return violations |
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} |
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// MarshalJSON marshals the linked list into JSON. Usually, you should use |
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// json.Marshal function for marshaling purposes. |
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func (list *ViolationList) MarshalJSON() ([]byte, error) { |
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b := bytes.Buffer{} |
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b.WriteRune('[') |
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for e := list.first; e != nil; e = e.next { |
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data, err := json.Marshal(e.violation) |
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if err != nil { |
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return nil, fmt.Errorf("failed to marshal violation: %w", err) |
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} |
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b.Write(data) |
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if e.next != nil { |
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b.WriteRune(',') |
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} |
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} |
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b.WriteRune(']') |
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return b.Bytes(), nil |
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} |
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// Next returns next element of the linked list. |
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func (element *ViolationListElement) Next() *ViolationListElement { |
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return element.next |
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} |
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// Violation returns underlying violation value. |
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func (element *ViolationListElement) Violation() Violation { |
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return element.violation |
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} |
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func (element *ViolationListElement) Error() string { |
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return element.violation.Error() |
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} |
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func (element *ViolationListElement) Code() string { |
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return element.violation.Code() |
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} |
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func (element *ViolationListElement) Is(codes ...string) bool { |
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return element.violation.Is(codes...) |
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} |
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func (element *ViolationListElement) Message() string { |
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return element.violation.Message() |
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} |
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func (element *ViolationListElement) MessageTemplate() string { |
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return element.violation.MessageTemplate() |
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} |
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func (element *ViolationListElement) Parameters() []TemplateParameter { |
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return element.violation.Parameters() |
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} |
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func (element *ViolationListElement) PropertyPath() *PropertyPath { |
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return element.violation.PropertyPath() |
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} |
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// IsViolation can be used to verify that the error implements the Violation interface. |
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func IsViolation(err error) bool { |
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var violation Violation |
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return errors.As(err, &violation) |
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} |
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// IsViolationList can be used to verify that the error implements the ViolationList. |
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func IsViolationList(err error) bool { |
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var violations *ViolationList |
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return errors.As(err, &violations) |
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} |
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// UnwrapViolation is a short function to unwrap Violation from the error. |
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func UnwrapViolation(err error) (Violation, bool) { |
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var violation Violation |
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as := errors.As(err, &violation) |
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return violation, as |
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} |
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// UnwrapViolationList is a short function to unwrap ViolationList from the error. |
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func UnwrapViolationList(err error) (*ViolationList, bool) { |
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var violations *ViolationList |
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328
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as := errors.As(err, &violations) |
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return violations, as |
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} |
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type internalViolation struct { |
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code string |
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message string |
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messageTemplate string |
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parameters []TemplateParameter |
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propertyPath *PropertyPath |
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} |
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func (v internalViolation) Is(codes ...string) bool { |
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1 |
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for _, code := range codes { |
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1 |
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if v.code == code { |
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1 |
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return true |
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} |
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} |
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return false |
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} |
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func (v internalViolation) Error() string { |
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var s strings.Builder |
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1 |
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s.Grow(32) |
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v.writeToBuilder(&s) |
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return s.String() |
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} |
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func (v internalViolation) writeToBuilder(s *strings.Builder) { |
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s.WriteString("violation") |
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1 |
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if v.propertyPath != nil { |
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s.WriteString(" at '" + v.propertyPath.String() + "'") |
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} |
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s.WriteString(": " + v.message) |
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} |
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func (v internalViolation) Code() string { |
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return v.code |
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} |
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func (v internalViolation) Message() string { |
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return v.message |
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} |
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|
|
375
|
|
|
func (v internalViolation) MessageTemplate() string { |
376
|
|
|
return v.messageTemplate |
377
|
|
|
} |
378
|
|
|
|
379
|
|
|
func (v internalViolation) Parameters() []TemplateParameter { |
380
|
|
|
return v.parameters |
381
|
|
|
} |
382
|
|
|
|
383
|
|
|
func (v internalViolation) PropertyPath() *PropertyPath { |
384
|
1 |
|
return v.propertyPath |
385
|
|
|
} |
386
|
|
|
|
387
|
|
|
func (v internalViolation) MarshalJSON() ([]byte, error) { |
388
|
1 |
|
return json.Marshal(struct { |
389
|
|
|
Code string `json:"code"` |
390
|
|
|
Message string `json:"message"` |
391
|
|
|
PropertyPath *PropertyPath `json:"propertyPath,omitempty"` |
392
|
|
|
}{ |
393
|
|
|
Code: v.code, |
394
|
|
|
Message: v.message, |
395
|
|
|
PropertyPath: v.propertyPath, |
396
|
|
|
}) |
397
|
|
|
} |
398
|
|
|
|
399
|
|
|
type internalViolationFactory struct { |
400
|
|
|
translator *Translator |
401
|
|
|
} |
402
|
|
|
|
403
|
|
|
func newViolationFactory(translator *Translator) *internalViolationFactory { |
404
|
1 |
|
return &internalViolationFactory{translator: translator} |
405
|
|
|
} |
406
|
|
|
|
407
|
|
|
func (factory *internalViolationFactory) CreateViolation( |
408
|
|
|
code, |
409
|
|
|
messageTemplate string, |
410
|
|
|
pluralCount int, |
411
|
|
|
parameters []TemplateParameter, |
412
|
|
|
propertyPath *PropertyPath, |
413
|
|
|
lang language.Tag, |
414
|
|
|
) Violation { |
415
|
1 |
|
message := factory.translator.translate(lang, messageTemplate, pluralCount) |
416
|
|
|
|
417
|
1 |
|
for i := range parameters { |
418
|
1 |
|
if parameters[i].NeedsTranslation { |
419
|
1 |
|
parameters[i].Value = factory.translator.translate(lang, parameters[i].Value, 0) |
420
|
|
|
} |
421
|
|
|
} |
422
|
|
|
|
423
|
1 |
|
return &internalViolation{ |
424
|
|
|
code: code, |
425
|
|
|
message: renderMessage(message, parameters), |
426
|
|
|
messageTemplate: messageTemplate, |
427
|
|
|
parameters: parameters, |
428
|
|
|
propertyPath: propertyPath, |
429
|
|
|
} |
430
|
|
|
} |
431
|
|
|
|
432
|
|
|
// ViolationBuilder used to build an instance of a Violation. |
433
|
|
|
type ViolationBuilder struct { |
434
|
|
|
code string |
435
|
|
|
messageTemplate string |
436
|
|
|
pluralCount int |
437
|
|
|
parameters []TemplateParameter |
438
|
|
|
propertyPath *PropertyPath |
439
|
|
|
language language.Tag |
440
|
|
|
|
441
|
|
|
violationFactory ViolationFactory |
442
|
|
|
} |
443
|
|
|
|
444
|
|
|
// NewViolationBuilder creates a new ViolationBuilder. |
445
|
|
|
func NewViolationBuilder(factory ViolationFactory) *ViolationBuilder { |
446
|
1 |
|
return &ViolationBuilder{violationFactory: factory} |
447
|
|
|
} |
448
|
|
|
|
449
|
|
|
// BuildViolation creates a new ViolationBuilder for composing Violation object fluently. |
450
|
|
|
func (b *ViolationBuilder) BuildViolation(code, message string) *ViolationBuilder { |
451
|
1 |
|
return &ViolationBuilder{ |
452
|
|
|
code: code, |
453
|
|
|
messageTemplate: message, |
454
|
|
|
violationFactory: b.violationFactory, |
455
|
|
|
} |
456
|
|
|
} |
457
|
|
|
|
458
|
|
|
// SetParameters sets template parameters that can be injected into the violation message. |
459
|
|
|
func (b *ViolationBuilder) SetParameters(parameters ...TemplateParameter) *ViolationBuilder { |
460
|
1 |
|
b.parameters = parameters |
461
|
|
|
|
462
|
1 |
|
return b |
463
|
|
|
} |
464
|
|
|
|
465
|
|
|
// AddParameter adds one parameter into a slice of parameters. |
466
|
|
|
func (b *ViolationBuilder) AddParameter(name, value string) *ViolationBuilder { |
467
|
1 |
|
b.parameters = append(b.parameters, TemplateParameter{Key: name, Value: value}) |
468
|
|
|
|
469
|
1 |
|
return b |
470
|
|
|
} |
471
|
|
|
|
472
|
|
|
// SetPropertyPath sets a property path of violated attribute. |
473
|
|
|
func (b *ViolationBuilder) SetPropertyPath(path *PropertyPath) *ViolationBuilder { |
474
|
1 |
|
b.propertyPath = path |
475
|
|
|
|
476
|
1 |
|
return b |
477
|
|
|
} |
478
|
|
|
|
479
|
|
|
// SetPluralCount sets a plural number that will be used for message pluralization during translations. |
480
|
|
|
func (b *ViolationBuilder) SetPluralCount(pluralCount int) *ViolationBuilder { |
481
|
1 |
|
b.pluralCount = pluralCount |
482
|
|
|
|
483
|
1 |
|
return b |
484
|
|
|
} |
485
|
|
|
|
486
|
|
|
// SetLanguage sets language that will be used to translate the violation message. |
487
|
|
|
func (b *ViolationBuilder) SetLanguage(tag language.Tag) *ViolationBuilder { |
488
|
1 |
|
b.language = tag |
489
|
|
|
|
490
|
1 |
|
return b |
491
|
|
|
} |
492
|
|
|
|
493
|
|
|
// CreateViolation creates a new violation with given parameters and returns it. |
494
|
|
|
// Violation is created by calling the CreateViolation method of the ViolationFactory. |
495
|
|
|
func (b *ViolationBuilder) CreateViolation() Violation { |
496
|
1 |
|
return b.violationFactory.CreateViolation( |
497
|
|
|
b.code, |
498
|
|
|
b.messageTemplate, |
499
|
|
|
b.pluralCount, |
500
|
|
|
b.parameters, |
501
|
|
|
b.propertyPath, |
502
|
|
|
b.language, |
503
|
|
|
) |
504
|
|
|
} |
505
|
|
|
|