Struct ApiError 

pub struct ApiError {
    pub status: u16,
    pub message: String,
}

A failure with the HTTP status to report it under. Body and parse problems are 400; a write that does not come from a page this server served is 403 or 415; an endpoint or an action nobody offers is 404; an endpoint reached by the wrong method is 405; a body past the size cap is 413; and filesystem and serialization failures are 500.

Fields

status: u16

message: String

Implementations

impl ApiError

pub fn new(status: u16, message: impl Into<String>) -> Self

Examples found in repository

examples/library/main.rs (line 816)

    fn render(&self, args: &ViewArgs, ctx: &Context) -> Result<ViewData, ApiError> {
        let branches: Vec<Branch> = ctx.optional_rows(BRANCHES_FILE)?;
        let books: Vec<Book> = ctx.optional_rows(BOOKS_FILE)?;
        let code = args.get_or("branch", "");
        let branch = branches
            .iter()
            .find(|b| b.code == code)
            .ok_or_else(|| ApiError::new(404, format!("no branch has the code \"{code}\"")))?;

        let (here, out) = shelf_counts(&books, code);
        let now = today();

        // What is out, with how it stands against its due date. A row's own
        // link is the catalogue entry, and one book's link is a `javascript:`
        // URL, which the page shows as text rather than following.
        let mut lent = DetailSection::main("Out on loan");
        for book in BranchDetail::by_rating(&books, code, true) {
            let late = days_from_civil(&book.due).map(|due| now - due);
            let mut row = DetailRow::new(book.title.as_str()).link(book.link.as_str());
            if !book.due.is_empty() {
                row = row.fact(format!("due {}", book.due));
            }
            row = match late {
                Some(days) if days > 0 => row.fact(format!("{days} day(s) late")),
                Some(days) => row.fact(format!("{} day(s) to go", -days)),
                None => row.note("No due date is recorded."),
            };
            lent = lent.row(row.button(Button::disabled("Chase the borrower", "Not built yet")));
        }
        if out == 0 {
            lent = lent.note("Everything this branch holds is on the shelf.");
        }

        // What can go out, ranked, with the one action this example offers.
        let mut shelf = DetailSection::main("On the shelf")
            .numbered()
            .note("Best rated first.");
        for book in BranchDetail::by_rating(&books, code, false) {
            let mut row = DetailRow::new(book.title.as_str());
            if let Some(rating) = book.rating {
                row = row.fact(format!("rated {rating}"));
            }
            if let Some(year) = book.year {
                row = row.fact(year);
            }
            if !book.notes.trim().is_empty() {
                row = row.note(book.notes.as_str());
            }
            shelf = shelf.row(
                row.button(Button::link("Catalogue", book.link.as_str()))
                    .button(Button::form(
                        "Lend it out",
                        BranchDetail::loan_form(&book.title),
                    )),
            );
        }
        if here == out {
            shelf = shelf.note("Nothing this branch holds is on the shelf today.");
        }

        let mut hours = DetailSection::side("When it is open").collapsed_on_phone();
        for (day, open) in &branch.hours {
            hours = hours.row(DetailRow::new(day.as_str()).fact(open.as_str()));
        }
        if branch.hours.is_empty() {
            hours = hours.note("No hours are recorded for this branch.");
        }

        // A count per genre, which is a section of facts rather than of things
        // to do, so it sits beside the page rather than in it.
        let mut counts: BTreeMap<&str, usize> = BTreeMap::new();
        for book in books.iter().filter(|b| b.shelved.contains_key(code)) {
            *counts.entry(book.genre.as_str()).or_default() += 1;
        }
        let mut genres = DetailSection::side("Genres here");
        for (genre, count) in counts {
            genres = genres.row(DetailRow::new(genre).fact(count));
        }

        Ok(ViewData::new().detail(
            Detail::new(branch.name.as_str())
                .status(if branch.open.unwrap_or(false) {
                    Status::new("Open", Tone::Good)
                } else {
                    Status::new("Shut", Tone::Neutral)
                })
                .subtitle(format!(
                    "{}, {} staff, {here} book(s) here, {out} out",
                    librarian(branch),
                    branch.staff.unwrap_or(0)
                ))
                .back(ViewLink::new("all-branches"))
                .section(lent)
                .section(shelf)
                .section(hours)
                .section(genres),
        ))
    }

    /// Which action was asked for. The router only lets through a name a
    /// button on this page offers, so the arm at the end is unreachable; it is
    /// written all the same, because a page with two actions on it decides
    /// between them here and that is what a consumer copies.
    fn act(
        &self,
        name: &str,
        fields: &Fields,
        args: &ViewArgs,
        ctx: &Context,
    ) -> Result<String, ApiError> {
        match name {
            "lend-a-book" => BranchDetail::lend(fields, args, ctx),
            _ => Err(ApiError::new(
                404,
                format!("this page has no action called \"{name}\""),
            )),
        }
    }

pub fn bad_request(message: impl Into<String>) -> Self

A malformed request the client should not repeat unchanged (400).

Examples found in repository

examples/library/main.rs (line 951)

    fn lend(fields: &Fields, args: &ViewArgs, ctx: &Context) -> Result<String, ApiError> {
        let title = args.get_or("title", "");
        let borrower = fields.text("borrower");
        let days = fields.integer("days")?;
        let from = fields.date("from")?;
        let condition = fields.text("condition").to_lowercase();

        if borrower.is_empty() {
            return Err(ApiError::bad_request("a loan needs a borrower"));
        }
        if days < 1 {
            return Err(ApiError::bad_request("a loan is at least one day long"));
        }
        let start = days_from_civil(from).ok_or_else(|| {
            ApiError::bad_request(format!("{from} is not a date in the calendar"))
        })?;
        let due = civil_from_days(start + days);

        let mut books: Vec<Book> = ctx.rows(BOOKS_FILE)?;
        let book = books
            .iter_mut()
            .find(|b| b.title == title)
            .ok_or_else(|| ApiError::bad_request(format!("no book is called \"{title}\"")))?;
        if book.lent.unwrap_or(false) {
            return Err(ApiError::bad_request(format!("\"{title}\" is already out")));
        }
        book.lent = Some(true);
        book.due = due.clone();
        book.notes = format!("Lent to {borrower} on {from}, {condition}.");

        let problems = Books.validate(&books, ctx)?;
        if let Some(first) = problems.first() {
            return Err(ApiError::bad_request(format!(
                "the loan would leave row {} in a state the table refuses: {}",
                first.line, first.message
            )));
        }

        let text = Books
            .serialize(&books)
            .map_err(|e| ApiError::server(format!("could not serialize {BOOKS_FILE}: {e}")))?;
        ctx.write(BOOKS_FILE, &text)?;

        Ok(format!("\"{title}\" is out to {borrower} until {due}."))
    }

pub fn server(message: impl Into<String>) -> Self

A failure on this side of the wire (500).

Examples found in repository

examples/library/main.rs (line 983)

    fn lend(fields: &Fields, args: &ViewArgs, ctx: &Context) -> Result<String, ApiError> {
        let title = args.get_or("title", "");
        let borrower = fields.text("borrower");
        let days = fields.integer("days")?;
        let from = fields.date("from")?;
        let condition = fields.text("condition").to_lowercase();

        if borrower.is_empty() {
            return Err(ApiError::bad_request("a loan needs a borrower"));
        }
        if days < 1 {
            return Err(ApiError::bad_request("a loan is at least one day long"));
        }
        let start = days_from_civil(from).ok_or_else(|| {
            ApiError::bad_request(format!("{from} is not a date in the calendar"))
        })?;
        let due = civil_from_days(start + days);

        let mut books: Vec<Book> = ctx.rows(BOOKS_FILE)?;
        let book = books
            .iter_mut()
            .find(|b| b.title == title)
            .ok_or_else(|| ApiError::bad_request(format!("no book is called \"{title}\"")))?;
        if book.lent.unwrap_or(false) {
            return Err(ApiError::bad_request(format!("\"{title}\" is already out")));
        }
        book.lent = Some(true);
        book.due = due.clone();
        book.notes = format!("Lent to {borrower} on {from}, {condition}.");

        let problems = Books.validate(&books, ctx)?;
        if let Some(first) = problems.first() {
            return Err(ApiError::bad_request(format!(
                "the loan would leave row {} in a state the table refuses: {}",
                first.line, first.message
            )));
        }

        let text = Books
            .serialize(&books)
            .map_err(|e| ApiError::server(format!("could not serialize {BOOKS_FILE}: {e}")))?;
        ctx.write(BOOKS_FILE, &text)?;

        Ok(format!("\"{title}\" is out to {borrower} until {due}."))
    }

pub fn from_parse(file: &str, err: &ParseError) -> Self

An unparseable line of a stored table (500): the file is the server’s to keep readable, so a client cannot fix it by retrying.

Trait Implementations

impl Clone for ApiError

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ApiError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for ApiError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for ApiError

impl Error for ApiError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl PartialEq for ApiError

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for ApiError