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Signed URLs

A signed URL is a normal web link with an embedded cryptographic signature attached. Anyone who has the link can access the resource at that URL — but only until the link expires. After expiry the link stops working automatically.

This lets you share a file from a private site with someone who does not have an ECMWF account, without making the entire site public or managing their access individually.

When to use signed URLs

  • You want to share a single file from a private site publicly, temporarily.
  • You are sending a download link in an email or a report.
  • You need an external service to pull a file from your site without credentials.

Getting a content manager

Signed URL operations require a SiteContentManagement instance with admin rights over the site:

from sites.sdk.sites import Site, Authenticator

site = Site.from_space_and_name(space='docs', name='my-project')
content_manager = site.get_content_manager(
    authenticator=Authenticator.from_token(token='<admin_site_bearer_token>')
)

Generating a signed URL

from sites.sdk.sites.utils import SiteAccessPermission

result = content_manager.generate_signed_url(
    target_url='https://sites.ecmwf.int/docs/my-project/reports/2026-Q1.pdf',
    duration=3600,                           # valid for 1 hour (3600 seconds)
    permission=SiteAccessPermission.Read
)

signed_link = result['data']['url']
print(signed_link)
# https://sites.ecmwf.int/docs/my-project/reports/2026-Q1.pdf?sig=abc123...

target_url must be the full, absolute URL to the resource on the Sites platform.

Common duration values:

Duration (seconds) Human-readable
3600 1 hour
86400 1 day
604800 7 days

Permission values:

SiteAccessPermission.Read       # link can only read/download the resource
SiteAccessPermission.ReadWrite  # link can also write (advanced use case)

Verifying a signed URL

Before consuming a signed URL you can verify that it is still valid and has not expired:

verification = content_manager.verify_signed_url(
    url='https://sites.ecmwf.int/docs/my-project/reports/2026-Q1.pdf?sig=abc123...'
)
print(verification)
# {'data': {'valid': True, 'permission': 'r', 'expiry': '2026-03-16T11:00:00'}, 'status': 'OK'}

If the URL has expired or was not produced by this site, the response will indicate it is invalid.

End-to-end example

The script below generates a signed URL, prints it, and then verifies it:

from sites.sdk.sites import Site, Authenticator
from sites.sdk.sites.utils import SiteAccessPermission

site = Site.from_space_and_name(space='docs', name='my-project')
mgr = site.get_content_manager(
    authenticator=Authenticator.from_token(token='<admin_site_bearer_token>')
)

base_url = 'https://sites.ecmwf.int'
file_path = 'reports/annual-report-2026.pdf'
full_url = f'{base_url}/{site.custom_space}/{site.site_name}/{file_path}'

# Generate the link — valid for 24 hours
result = mgr.generate_signed_url(
    target_url=full_url,
    duration=86400,
    permission=SiteAccessPermission.Read
)
signed_url = result['data']['url']
print('Share this link:')
print(signed_url)

# Verify the link is valid before sending it out
verification = mgr.verify_signed_url(url=signed_url)
if verification['data']['valid']:
    print('Link is valid until', verification['data']['expiry'])
else:
    print('Link is not valid!')

What's next?