---
name: "X509_load_http"
section: "3ssl"
platform: "linux"
package: "openssl"
version: "3.6.5-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/X509_load_http"
---

# X509\_load\_http(3ssl)

certificate and CRL loading functions

## NAME

X509\_load\_http, X509\_http\_nbio, X509\_CRL\_load\_http, X509\_CRL\_http\_nbio - certificate and CRL loading functions

## SYNOPSIS

```
 #include <openssl/x509.h>
 X509 *X509_load_http(const char *url, BIO *bio, BIO *rbio, int timeout);
 X509_CRL *X509_CRL_load_http(const char *url, BIO *bio, BIO *rbio, int timeout);
```

The following macros have been deprecated since OpenSSL 3.0, and can be hidden entirely by defining **OPENSSL\_API\_COMPAT** with a suitable version value, see **openssl\_user\_macros**(7):

```
 #define X509_http_nbio(rctx, pcert)
 #define X509_CRL_http_nbio(rctx, pcrl)
```

## DESCRIPTION

**X509\_load\_http()** and **X509\_CRL\_load\_http()** loads a certificate or a CRL, respectively, in ASN.1 format using HTTP from the given **url**.

Maximum size of the HTTP response is 100 kB for certificates and 32 MB for CRLs and hard coded in the functions.

If **bio** is given and **rbio** is NULL then this BIO is used instead of an internal one for connecting, writing the request, and reading the response. If both **bio** and **rbio** are given (which may be memory BIOs, for instance) then no explicit connection is attempted, **bio** is used for writing the request, and **rbio** for reading the response.

If the **timeout** parameter is \> 0 this indicates the maximum number of seconds to wait until the transfer is complete. A value of 0 enables waiting indefinitely, while a value \< 0 immediately leads to a timeout condition.

**X509\_http\_nbio()** and **X509\_CRL\_http\_nbio()** are macros for backward compatibility that have the same effect as the functions above but with infinite timeout and without the possibility to specify custom BIOs.

## RETURN VALUES

On success the function yield the loaded value, else NULL. Error conditions include connection/transfer timeout, parse errors, etc.

## SEE ALSO

**OSSL\_HTTP\_get**(3)

## HISTORY

**X509\_load\_http()** and **X509\_CRL\_load\_http()** were added in OpenSSL 3.0. **X509\_http\_nbio()** and **X509\_CRL\_http\_nbio()** were deprecated in OpenSSL 3.0.

## COPYRIGHT

Copyright 2019-2021 The OpenSSL Project Authors. All Rights Reserved.

Licensed under the Apache License 2.0 (the "License").  You may not use this file except in compliance with the License.  You can obtain a copy in the file LICENSE in the source distribution or at \<https://www.openssl.org/source/license.html\>.