halo-dev/halo · warning · ServerWebInputException

Required url is missing.

Error message

Required url is missing.

What it means

UploadFromUrlRequest is a record whose compact constructor validates required fields. It throws ServerWebInputException (HTTP 400) 'Required url is missing.' when the url component is null. The url field is annotated @Schema(requiredMode = REQUIRED), so the guard enforces that contract at construction time (i.e. when Spring binds the request body).

Source

Thrown at application/src/main/java/run/halo/app/core/attachment/endpoint/AttachmentEndpoint.java:138

    /**
     * Request payload for creating an attachment from a remote URL.
     *
     * @param url remote file URL to transfer into storage
     * @param policyName storage policy {@code metadata.name}
     * @param groupName attachment group {@code metadata.name}
     * @param filename custom file name
     */
    public record UploadFromUrlRequest(
            @Schema(requiredMode = REQUIRED) URL url,

            @Schema(requiredMode = REQUIRED) String policyName,

            String groupName,

            String filename) {
        public UploadFromUrlRequest {
            if (Objects.isNull(url)) {
                throw new ServerWebInputException("Required url is missing.");
            }

            if (!StringUtils.hasText(policyName)) {
                throw new ServerWebInputException("Policy name must not be blank");
            }
        }
    }

    /** Multipart payload for uploading an attachment. */
    @Schema(types = "object")
    public interface IUploadRequest {

        /** Attachment file. */
        @Schema(requiredMode = REQUIRED)
        FilePart getFile();

        /** Storage policy {@code metadata.name}. */
        @Schema(requiredMode = REQUIRED)

View on GitHub (pinned to d2f5165f9c)

Solutions

1. Include a non-null url in the JSON body of the upload-from-url request.
2. Disable the submit control on the client until a URL is entered.
3. If invoking the endpoint programmatically, assert url != null before serializing the body.

Example fix

// before
{ "policyName": "default" } // 400: url missing

// after
{ "url": "https://example.com/file.png", "policyName": "default" }

if (url == null) {
    return Mono.error(new ServerWebInputException("Required url is missing."));
}
// build UploadFromUrlRequest(url, policyName, groupName, filename)

static boolean hasUrl(URL url) { return url != null; }

When it happens

Trigger: POST to the upload-from-url attachment endpoint with a JSON body that omits "url", sends url:null, or sends a value that cannot be bound to java.net.URL (which may fail earlier in binding).

Common situations: Client form bug that doesn't send the url field; a UI that lets the user submit before entering a URL; integration code constructing the body from optional fields.

Related errors

• Policy name must not be blank
• Invalid part of policyName
• urls must not be empty.
• Invalid part of file
• Required url is missing.

AI-assisted analysis of halo-dev/halo@d2f5165f9c (2026-08-14). Data as JSON: /api/errors/40b7054d508d3852. Report an issue: GitHub.