Metadata fields

piko.Metadata is the struct returned as the second value from a page's Render function. Its fields control <title>, <meta>, social-sharing tags, canonical URLs, caching directives, and redirects. This page enumerates every field. For task recipes see the how-to guides on title and OG tags and structured data.

Schema

type Metadata struct {
    Title          string
    Description    string
    Keywords       string
    Language       string
    CanonicalURL   string
    RobotsRule     string
    Status         int
    StatusText     string
    ClientRedirect string
    ServerRedirect string
    RedirectStatus int
    LastModified   *time.Time
    CacheKey       string
    OGTags         []OGTag
    MetaTags       []MetaTag
    TwitterCards   []MetaTag
    StructuredData []string
    AlternateLinks []map[string]string
}

InternalMetadata embeds Metadata and also embeds CachePolicy. Pages set the cache fields (Key, MaxAgeSeconds, Enabled, OnRender, Static, MustRevalidate, NoStore) on the same returned struct. The renderer flattens them into the same JSON document at render time.

Field reference

OGTag

type OGTag struct {
    Property string
    Content  string
}

Common properties: og:title, og:description, og:type, og:url, og:image, og:site_name.

MetaTag

type MetaTag struct {
    Name    string
    Content string
}

AlternateLinks entries

Each entry is a map[string]string whose keys are the rendered attribute names. The renderer does not fix a schema, so any combination works:

metadata.AlternateLinks = []map[string]string{
    {"hreflang": "en-GB", "href": "https://example.com/en-gb/"},
    {"hreflang": "fr",    "href": "https://example.com/fr/"},
    {"media": "only screen and (max-width: 640px)", "href": "https://m.example.com/"},
}

The unrelated seo_dto.AlternateLink struct (used by sitemap generation) is not the type used here.

Status handling

Callers write Metadata.Status and Metadata.StatusText, but the response writer does not read them. Successful renders unconditionally write 200 OK. Non-200 status codes come from typed errors returned by Render, not from these fields. The pikotest harness still inspects Metadata.Status (so unit-test assertions on the field continue to behave as written), but production responses ignore it.

To return a non-200 status from a page, return a typed error from Render (for example &piko.NotFoundError{Message: "..."} or &piko.GenericPageError{Status: 503, Message: "..."}). See the errors reference for the full error-type-to-status mapping. For redirects, set ClientRedirect (or ServerRedirect) and RedirectStatus instead of Status.

Redirects

ClientRedirect sends an HTTP redirect response, so the browser's address bar changes. ServerRedirect rewrites the response in-process, so the browser's address bar does not change.

When both ServerRedirect and ClientRedirect carry values, ServerRedirect takes precedence.

Set RedirectStatus alongside ClientRedirect. Piko defaults to 302 (Found) when you omit RedirectStatus or supply an unsupported value, and ignores RedirectStatus entirely when ClientRedirect is empty. ServerRedirect is an internal rewrite, so the inner page's response writer controls the status code. RedirectStatus is not consulted.

See also

• Title and OG tags how-to.
• Structured data how-to.
• Routing rules reference for status codes returned via typed errors.
• Errors reference.

Used in. Every page with custom metadata, including scenarios 001 through 020.