Struct Client 

pub struct Client {
    pub base_url: String,
    /* private fields */
}

Fetch indicator observations.

Arguments

• countries: ISO2/ISO3 country codes or aggregate codes ("DEU", "USA", "EUU"…). Multiple codes are allowed; they are joined for the API (e.g., "DEU;USA").
• indicators: Indicator IDs ("SP.POP.TOTL", …). Multiple allowed.
• date: A single year (Year(2020)) or an inclusive range (Range { start, end }).
• source: Optional numeric source id (e.g., 2 for WDI). Required by the API when requesting multiple indicators.

Returns

A Vec<models::DataPoint> where one row equals one observation (country, indicator, year).

Errors

• Network/HTTP error
• JSON decoding error
• API-level error payload (surfaced as an error)

Example

let cli = Client::default();
let data = cli.fetch(
    &["DEU".into(), "USA".into()],
    &["SP.POP.TOTL".into()],
    Some(DateSpec::Range { start: 2015, end: 2020 }),
    None,
)?;

Fields

base_url: String

Implementations

impl Client

pub fn fetch_indicator_units( &self, indicators: &[String], ) -> Result<HashMap<String, String>>

Fetch units from the World Bank indicator endpoint for the given indicators.

Returns a map from indicator ID to unit string. Missing indicators or those without units will not be present in the returned HashMap.

Arguments

• indicators: Indicator IDs to fetch metadata for (e.g., ["SP.POP.TOTL"]).

Errors

Returns an error if:

• Network request fails or times out
• HTTP response status is not successful (non-2xx)
• Response body cannot be parsed as JSON
• API returns an error message in the response

Example

let cli = Client::default();
let units = cli.fetch_indicator_units(&["SP.POP.TOTL".into()])?;

pub fn fetch( &self, countries: &[String], indicators: &[String], date: Option<DateSpec>, source: Option<u32>, ) -> Result<Vec<DataPoint>>

Fetch indicator observations.

Arguments

• countries: ISO2 (e.g., “DE”) or ISO3 (e.g., “DEU”) or aggregates (e.g., “EUU”). Multiple accepted.
• indicators: e.g., “SP.POP.TOTL”. Multiple accepted.
• date: A single year or inclusive range.
• source: Optional numeric source id (e.g., 2 for WDI). Required by the World Bank API for efficient single-call multi-indicator requests. When source is None and multiple indicators are requested, this method automatically falls back to individual requests per indicator and merges the results.

Errors

Returns an error if:

• No countries provided (empty slice)
• No indicators provided (empty slice)
• Network request fails or times out
• HTTP response status is not successful (non-2xx)
• Response body cannot be parsed as JSON
• API returns an error message in the response
• Page limit exceeded (safety limit: 1000 pages)

Trait Implementations

impl Clone for Client

fn clone(&self) -> Client

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for Client

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

Formats the value using the given formatter.

impl Default for Client

fn default() -> Self

Returns the “default value” for a type.