package survey import ( "errors" "io" "os" "strings" "github.com/AlecAivazis/survey/v2/core" "github.com/AlecAivazis/survey/v2/terminal" ) // DefaultAskOptions is the default options on ask, using the OS stdio. func defaultAskOptions() *AskOptions { return &AskOptions{ Stdio: terminal.Stdio{ In: os.Stdin, Out: os.Stdout, Err: os.Stderr, }, PromptConfig: PromptConfig{ PageSize: 7, HelpInput: "?", Icons: IconSet{ Error: Icon{ Text: "X", Format: "red", }, Help: Icon{ Text: "?", Format: "cyan", }, Question: Icon{ Text: "?", Format: "green+hb", }, MarkedOption: Icon{ Text: "[x]", Format: "green", }, UnmarkedOption: Icon{ Text: "[ ]", Format: "default+hb", }, SelectFocus: Icon{ Text: ">", Format: "cyan+b", }, }, Filter: func(filter string, value string, index int) (include bool) { filter = strings.ToLower(filter) // include this option if it matches return strings.Contains(strings.ToLower(value), filter) }, KeepFilter: false, }, } } func defaultPromptConfig() *PromptConfig { return &defaultAskOptions().PromptConfig } func defaultIcons() *IconSet { return &defaultPromptConfig().Icons } // OptionAnswer is an ergonomic alias for core.OptionAnswer type OptionAnswer = core.OptionAnswer // Icon holds the text and format to show for a particular icon type Icon struct { Text string Format string } // IconSet holds the icons to use for various prompts type IconSet struct { HelpInput Icon Error Icon Help Icon Question Icon MarkedOption Icon UnmarkedOption Icon SelectFocus Icon } // Validator is a function passed to a Question after a user has provided a response. // If the function returns an error, then the user will be prompted again for another // response. type Validator func(ans interface{}) error // Transformer is a function passed to a Question after a user has provided a response. // The function can be used to implement a custom logic that will result to return // a different representation of the given answer. // // Look `TransformString`, `ToLower` `Title` and `ComposeTransformers` for more. type Transformer func(ans interface{}) (newAns interface{}) // Question is the core data structure for a survey questionnaire. type Question struct { Name string Prompt Prompt Validate Validator Transform Transformer } // PromptConfig holds the global configuration for a prompt type PromptConfig struct { PageSize int Icons IconSet HelpInput string Filter func(filter string, option string, index int) bool KeepFilter bool } // Prompt is the primary interface for the objects that can take user input // and return a response. type Prompt interface { Prompt(config *PromptConfig) (interface{}, error) Cleanup(*PromptConfig, interface{}) error Error(*PromptConfig, error) error } // PromptAgainer Interface for Prompts that support prompting again after invalid input type PromptAgainer interface { PromptAgain(config *PromptConfig, invalid interface{}, err error) (interface{}, error) } // AskOpt allows setting optional ask options. type AskOpt func(options *AskOptions) error // AskOptions provides additional options on ask. type AskOptions struct { Stdio terminal.Stdio Validators []Validator PromptConfig PromptConfig } // WithStdio specifies the standard input, output and error files survey // interacts with. By default, these are os.Stdin, os.Stdout, and os.Stderr. func WithStdio(in terminal.FileReader, out terminal.FileWriter, err io.Writer) AskOpt { return func(options *AskOptions) error { options.Stdio.In = in options.Stdio.Out = out options.Stdio.Err = err return nil } } // WithFilter specifies the default filter to use when asking questions. func WithFilter(filter func(filter string, value string, index int) (include bool)) AskOpt { return func(options *AskOptions) error { // save the filter internally options.PromptConfig.Filter = filter return nil } } // WithKeepFilter sets the if the filter is kept after selections func WithKeepFilter(KeepFilter bool) AskOpt { return func(options *AskOptions) error { // set the page size options.PromptConfig.KeepFilter = KeepFilter // nothing went wrong return nil } } // WithValidator specifies a validator to use while prompting the user func WithValidator(v Validator) AskOpt { return func(options *AskOptions) error { // add the provided validator to the list options.Validators = append(options.Validators, v) // nothing went wrong return nil } } type wantsStdio interface { WithStdio(terminal.Stdio) } // WithPageSize sets the default page size used by prompts func WithPageSize(pageSize int) AskOpt { return func(options *AskOptions) error { // set the page size options.PromptConfig.PageSize = pageSize // nothing went wrong return nil } } // WithHelpInput changes the character that prompts look for to give the user helpful information. func WithHelpInput(r rune) AskOpt { return func(options *AskOptions) error { // set the input character options.PromptConfig.HelpInput = string(r) // nothing went wrong return nil } } // WithIcons sets the icons that will be used when prompting the user func WithIcons(setIcons func(*IconSet)) AskOpt { return func(options *AskOptions) error { // update the default icons with whatever the user says setIcons(&options.PromptConfig.Icons) // nothing went wrong return nil } } /* AskOne performs the prompt for a single prompt and asks for validation if required. Response types should be something that can be casted from the response type designated in the documentation. For example: name := "" prompt := &survey.Input{ Message: "name", } survey.AskOne(prompt, &name) */ func AskOne(p Prompt, response interface{}, opts ...AskOpt) error { err := Ask([]*Question{{Prompt: p}}, response, opts...) if err != nil { return err } return nil } /* Ask performs the prompt loop, asking for validation when appropriate. The response type can be one of two options. If a struct is passed, the answer will be written to the field whose name matches the Name field on the corresponding question. Field types should be something that can be casted from the response type designated in the documentation. Note, a survey tag can also be used to identify a Otherwise, a map[string]interface{} can be passed, responses will be written to the key with the matching name. For example: qs := []*survey.Question{ { Name: "name", Prompt: &survey.Input{Message: "What is your name?"}, Validate: survey.Required, Transform: survey.Title, }, } answers := struct{ Name string }{} err := survey.Ask(qs, &answers) */ func Ask(qs []*Question, response interface{}, opts ...AskOpt) error { // build up the configuration options options := defaultAskOptions() for _, opt := range opts { if opt == nil { continue } if err := opt(options); err != nil { return err } } // if we weren't passed a place to record the answers if response == nil { // we can't go any further return errors.New("cannot call Ask() with a nil reference to record the answers") } // go over every question for _, q := range qs { // If Prompt implements controllable stdio, pass in specified stdio. if p, ok := q.Prompt.(wantsStdio); ok { p.WithStdio(options.Stdio) } // grab the user input and save it ans, err := q.Prompt.Prompt(&options.PromptConfig) // if there was a problem if err != nil { return err } // build up a list of validators that we have to apply to this question validators := []Validator{} // make sure to include the question specific one if q.Validate != nil { validators = append(validators, q.Validate) } // add any "global" validators for _, validator := range options.Validators { validators = append(validators, validator) } // apply every validator to thte response for _, validator := range validators { // wait for a valid response for invalid := validator(ans); invalid != nil; invalid = validator(ans) { err := q.Prompt.Error(&options.PromptConfig, invalid) // if there was a problem if err != nil { return err } // ask for more input if promptAgainer, ok := q.Prompt.(PromptAgainer); ok { ans, err = promptAgainer.PromptAgain(&options.PromptConfig, ans, invalid) } else { ans, err = q.Prompt.Prompt(&options.PromptConfig) } // if there was a problem if err != nil { return err } } } if q.Transform != nil { // check if we have a transformer available, if so // then try to acquire the new representation of the // answer, if the resulting answer is not nil. if newAns := q.Transform(ans); newAns != nil { ans = newAns } } // tell the prompt to cleanup with the validated value q.Prompt.Cleanup(&options.PromptConfig, ans) // if something went wrong if err != nil { // stop listening return err } // add it to the map err = core.WriteAnswer(response, q.Name, ans) // if something went wrong if err != nil { return err } } // return the response return nil } // paginate returns a single page of choices given the page size, the total list of // possible choices, and the current selected index in the total list. func paginate(pageSize int, choices []core.OptionAnswer, sel int) ([]core.OptionAnswer, int) { var start, end, cursor int if len(choices) < pageSize { // if we dont have enough options to fill a page start = 0 end = len(choices) cursor = sel } else if sel < pageSize/2 { // if we are in the first half page start = 0 end = pageSize cursor = sel } else if len(choices)-sel-1 < pageSize/2 { // if we are in the last half page start = len(choices) - pageSize end = len(choices) cursor = sel - start } else { // somewhere in the middle above := pageSize / 2 below := pageSize - above cursor = pageSize / 2 start = sel - above end = sel + below } // return the subset we care about and the index return choices[start:end], cursor }