Function processBackgroundUrls

frontend/util/waveutil.ts:15–70

(cssText: string)

}

export function processBackgroundUrls(cssText: string): string {
    if (isBlank(cssText)) {
        return null;
    }
    cssText = cssText.trim();
    if (cssText.endsWith(";")) {
        cssText = cssText.slice(0, -1);
    }
    const attrRe = /^background(-image)?\s*:\s*/i;
    cssText = cssText.replace(attrRe, "");
    const ast = parseCSS("background: " + cssText, {
        context: "declaration",
    });
    let hasUnsafeUrl = false;
    walkCSS(ast, {
        visit: "Url",
        enter(node) {
            const originalUrl = node.value.trim();
            if (
                originalUrl.startsWith("http:") ||
                originalUrl.startsWith("https:") ||
                originalUrl.startsWith("data:")
            ) {
                return;
            }
            // allow file:/// urls (if they are absolute)
            if (originalUrl.startsWith("file://")) {
                const path = originalUrl.slice(7);
                if (!path.startsWith("/")) {
                    console.log(`Invalid background, contains a non-absolute file URL: ${originalUrl}`);
                    hasUnsafeUrl = true;
                    return;
                }
                const newUrl = encodeFileURL(path);
                node.value = newUrl;
                return;
            }
            // allow absolute paths
            if (originalUrl.startsWith("/") || originalUrl.startsWith("~/") || /^[a-zA-Z]:(\/|\\)/.test(originalUrl)) {
                const newUrl = encodeFileURL(originalUrl);
                node.value = newUrl;
                return;
            }
            hasUnsafeUrl = true;
            console.log(`Invalid background, contains an unsafe URL scheme: ${originalUrl}`);
        },
    });
    if (hasUnsafeUrl) {
        return null;
    }
    const rtnStyle = generateCSS(ast);
    if (rtnStyle == null) {
        return null;
    }
    return rtnStyle.replace(/^background:\s*/, "");
}

export function computeBgStyleFromMeta(meta: Omit<BackgroundConfigType, "display:name">, defaultOpacity: number = null): React.CSSProperties {