tonhowtf/omniget · error

Failed to build HTTP client

Error message

Failed to build HTTP client: {}

What it means

Thrown in DirectFileDownloader::download when reqwest::ClientBuilder::build() fails after applying proxy/cookie/timeout settings, mapped with anyhow! including the underlying reqwest error. It indicates the HTTP client could not be constructed at all — typically a TLS backend or proxy configuration problem, not a network failure of the request itself.

Solutions

  1. Read the wrapped reqwest error in the message — it names the failing builder setting.
  2. Check proxy env vars (HTTP_PROXY/HTTPS_PROXY/ALL_PROXY) and any global proxy config for malformed URLs; unset them to test.
  3. Ensure the reqwest TLS feature is enabled and CA certificates are present in the environment.
  4. Retry without the cookie jar / proxy overrides to isolate which builder option breaks.

Example fix

// before
let client = builder.build().map_err(|e| anyhow!("Failed to build HTTP client: {}", e))?;
// after: fall back to a default client when custom builder options are the problem
let client = builder.build().unwrap_or_else(|e| {
    tracing::warn!("client build failed ({}), using default", e);
    reqwest::Client::new()
});
Defensive patterns

Strategy: try-catch

Validate before calling

// check proxy env vars are well-formed before building
for v in ["HTTP_PROXY", "HTTPS_PROXY", "ALL_PROXY"] {
    if let Ok(p) = std::env::var(v) {
        url::Url::parse(&p).map_err(|_| anyhow!("{} is not a valid proxy URL: {}", v, p))?;
    }
}

Try / catch

match downloader.download(&info, &opts, tx).await {
    Err(e) if e.to_string().contains("Failed to build HTTP client") => {
        eprintln!("check proxy settings / TLS config: {}", e);
        // retry with proxies disabled:
        std::env::remove_var("HTTPS_PROXY");
        retry_download().await
    }
    other => other,
}

Prevention

When it happens

Trigger: Builder configured with an invalid or unreachable proxy (apply_global_proxy output), malformed cookie jar, or a reqwest build failure such as missing/unusable TLS backend (e.g. native-tls vs rustls mismatch) or invalid system proxy env vars.

Common situations: Users set HTTP_PROXY/HTTPS_PROXY env vars with invalid URLs; environments without CA certificates; builds with a TLS feature mismatch; corrupted cookie store configuration.

Understand the failure class

Background: "Invalid value" and "allowed values are" config errors: what your library rejected and how to fix it — this error's family across 41 libraries.

Related errors

AI-assisted analysis of tonhowtf/omniget@8600b91f42 (2026-09-12). Data as JSON: /api/errors/c9fe08dc27584b9a. Report an issue: GitHub.

Appendix: source

Thrown at src-tauri/omniget-core/src/platforms/direct_file.rs:248

            .connect_timeout(std::time::Duration::from_secs(30));

        if let Some(ua) = opts.user_agent.as_deref() {
            builder = builder.user_agent(ua);
        }

        let jar =
            crate::core::cookie_parser::load_extension_cookies_for_url(file_url).or_else(|| {
                opts.referer
                    .as_deref()
                    .and_then(crate::core::cookie_parser::load_extension_cookies_for_url)
            });
        if let Some(jar) = jar {
            builder = builder.cookie_provider(jar);
        }

        let client = builder
            .build()
            .map_err(|e| anyhow!("Failed to build HTTP client: {}", e))?;

        let mut headers = reqwest::header::HeaderMap::new();
        if let Some(ref r) = opts.referer {
            if let Ok(val) = reqwest::header::HeaderValue::from_str(r) {
                headers.insert(reqwest::header::REFERER, val);
            }
        }
        if let Some(ref hdrs) = opts.extra_headers {
            for (name, value) in hdrs {
                if let (Ok(hname), Ok(hval)) = (
                    reqwest::header::HeaderName::from_bytes(name.as_bytes()),
                    reqwest::header::HeaderValue::from_str(value),
                ) {
                    headers.insert(hname, hval);
                }
            }
        }
        http_client::inject_ua_header(&mut headers, opts.user_agent.as_deref());

View on GitHub (pinned to 8600b91f42)