presign_post ¶

def presign_post(
    self,
    bucket: "capo_s3.types.bucket_name.BucketName",
    key: "capo_s3.types.object_key.ObjectKey",
    *,
    expires_in: int = 3600,
    fields: Mapping[str, str] | None = None,
    conditions: Sequence[PostCondition] | None = None,
    config_overrides: S3ClientConfig | None = None,
) -> PresignedPost:
    """A form that uploads an object to the bucket, usable without credentials: POST its ``fields`` to its ``url`` as ``multipart/form-data``, followed by the ``file`` field.

    Args:
        bucket: The bucket to upload to.
        key: The key of the uploaded object. It is matched exactly, unless a ``starts-with`` condition on ``key`` says how it starts, which a key ending with ``${filename}`` needs.
        expires_in: How long the form stays valid, in seconds.
        fields: Form fields with a fixed value, such as ``acl`` or ``Content-Type``. Each is returned in ``fields`` and pinned to its value by the policy.
        conditions: Policy conditions on the fields the uploader adds, such as ``{"type": "starts-with", "field": "Content-Type", "prefix": "image/"}`` or ``{"type": "content-length-range", "min": 0, "max": 1048576}``. An ``eq`` condition has one value to send, so it is returned in ``fields`` like an entry of ``fields``.
    """
    _, options_ = self.operation_options(config_overrides)
    import capo_s3._operations.amazon_s3.head_bucket

    # The form posts to the bucket itself, which is where HeadBucket's request goes.
    request = capo_s3._operations.amazon_s3.head_bucket.build_request(
        options_, {"bucket": bucket}
    )
    signer = (request.context or {}).get("signer")
    if not isinstance(signer, SigV4Signer):
        raise RuntimeError("presign requires SigV4 credentials")
    creds = signer.provider.resolve_identity()
    return presign_post_sigv4(
        str(request.url),
        creds,
        signing_region=signer._auth_scheme["signingRegion"],
        bucket=bucket,
        key=key,
        expires_in=expires_in,
        fields=fields,
        conditions=conditions,
    )