DataScript: Functions
Introduction
DataScripts are comprised of any number of function or method calls which can be used to inspect and act on traffic flowing through a virtual service. DataScript’s functions are exposed via Lua libraries and grouped into modules: string, vs, http, pool, ssl and crypto. Other Lua libraries may also be used, following the documentation from lua.org. The following functions are available.
DataScript
| String | Description |
| string.beginswith( source, target ) | Search for string in beginning of a string |
| string.contains( source, target ) | Search contains a string in another string |
| string.endswith( source, target ) | Search for string at the end of a string |
| string.len( source ) | Returns number of characters in string |
| string.lower( source ) | Change a string to lower case |
| string.split( source_string, delimiter ) | Parses a string into substrings |
| string.sub( source, begin, [end] ) | Extract a sub-string from a string |
| string.upper( source ) | Change a string to upper case |
| L4 | |
| avi.l4.read(num_bytes) | Read the payload from the socket buffer. This function is available starting with 18.2.5. |
| avi.l4.collect(num_bytes) | Gather the num_bytes before subjecting the payload to the DataScript. This function is available starting with 18.2.5. |
| VS | |
| avi.vs.analytics.counter(metric_name, [operation], [value]) | Creates and manipulates a counter-type metric. Refer to User-defined Metrics. |
| avi.vs.analytics.gauge(metric_name, [operation], [value]) | Creates and manipulates a gauge-type metric. Refer to User-defined Metrics. |
| avi.vs.analytics.get_metric(metric_name, metric_type) | Return the user-defined metric value if one with the given name and given type exists. Refer to User-defined Metrics. |
| avi.vs.client_ip( ) | Returns the client IP address |
| avi.vs.client_port( ) | Returns the client source port |
| avi.vs.close_conn([reset]) | Close the current TCP/UDP connection |
| avi.vs.ip( ) | Returns IP address of the VS |
| avi.vs.log( ) | Write a custom log to VS > client logs |
| avi.vs.name( ) | Returns the name of the VS |
| avi.vs.port( ) | Returns the VS port of the connection |
| avi.vs.persist(key, [lifetime], [pool]) | Creates peristence entry using the key used after load balancing traffic |
| avi.vs.rate_limit( type, string_to_limit, [defer_action=False] ) | Rate limits entities of various kinds. |
| avi.vs.reqvar.* | Set a global variable usable across events |
| avi.vs.table_insert( [table_name,] key, value [, lifetime] ) | Store custom data in a time based table |
| avi.vs.table_lookup( [table_name,] key [, lifetime_exten] ) | Lookup data in a table |
| avi.vs.table_refresh( [table_name,] key [, lifetime_exten] ) | Update the expire time for a table entry |
| avi.vs.table_remove( [table_name,] key ) | Remove data from a table |
| avi.vs.se() | Returns the UUID of the service engine handling the request |
| HTTP | |
| avi.http.add_cookie( table ) | Insert a new cookie |
| avi.http.add_header( name, value ) | Insert a new header and value |
| avi.http.close_conn( [reset] ) | Close or reset a TCP connection |
| avi.http.cookie_exists( name, [context] ) | Validate if a cookie already exists |
| avi.http.disable() | Upgrade (disable) HTTP processing for the current connection, which will subsequently be treated as layer 4 TCP |
| avi.http.get_cookie( name [, context] ) | Return the values of a cookie |
| avi.http.get_cookie_names ( [context] ) | Return the names of cookies |
| avi.http.get_header( [[name] [context]] ) | Return header names or their values |
| avi.http.get_host_tokens( [start [, end]] ) | Return a subsection of the host |
| avi.http.get_path( [false] ) | Returns the URI's path /path.index.htm |
| avi.http.get_path_tokens( [start [, end]] ) | Return a subsection of the path |
| avi.http.get_query( [arg_name | avi.QUERY_TABLE] [, decode] ) | Returns the URI's query ?a=1&b=2 |
| avi.http.get_req_body([size_in_kb]) | Returns part or all of the client request body. |
| avi.http.get_request_id() | Returns the request ID. |
| avi.http.get_reqvar() | Gets (reads) data stored in a variable via the avi.http.set() function. |
| avi.http.get_response_body(size [, offset]) | Gets (reads) a specified number of kilobytes from the buffered response body starting at the specified kilobyte offset. |
| avi.http.get_uri( [false] ) | Returns the URI (path plus query) |
| avi.http.get_userid( ) | Returns the user ID for the session |
| avi.http.hostname( ) | Return the hostname requested by client |
| avi.http.internal_status() | Returns HTTP status as a string |
| avi.http.method( ) | Return the client's request method |
| avi.http.protocol( ) | Returns the session protocol, http or https |
| avi.http.redirect( uri [,status] ) | Redirect a request |
| avi.http.remove_cookie( name1, [name2, ...] ) | Remove an existing cookie |
| avi.http.remove_header( name ) | Remove all instances of a header |
| avi.http.replace_cookie( table ) | Replace an existing cookies values |
| avi.http.replace_header( name, value ) | Replace an existing header's value |
| avi.http.response( status, [headers, [body]] ) | Send a defined HTTP response page |
| avi.http.saml_session_decrypt( ) | Returns a string of the decrypted SAML session cookie if it exists; else nil |
| avi.http.scheme( ) | Returns http:// or https:// |
| avi.http.secure( ) | Returns on for https, nil for http |
| avi.http.set_path( new_uri ) | Modify the path of a request |
| avi.http.set_query( integer | string | table ) | Modify the query of a request |
| avi.http.set_reqvar() | Sets (write) arbitrary data from an HTTP request event into a variable. These variables have scope across the HTTP_REQ and HTTP_RESP events. |
| avi.http.set_response_body_buffer_size(size) | Sets the maximum response body to be buffered. |
| avi.http.set_server_timeout( time ) | Set a custom timeout value for a particular request. |
| avi.http.set_uri( new_uri ) | Change the URI |
| avi.http.set_userid( ) | Sets the user ID for the session |
| avi.http.status( ) | Returns status code to be sent to client |
| avi.http.disable_auth | Disables the client authentication |
| Pool | |
| avi.pool.get_server_status( pool, server, port ) | Returns the up/down status of the server |
| avi.pool.get_servers( pool ) | Returns up and total server count |
| avi.pool.get_active_server_list( pool ) | Returns the IP addresses of all active servers in a pool |
| avi.pool.select( pool [, server [, port]] ) | Pick a specific pool |
| avi.pool.server_ip( ) | Returns the IP of the selected server |
| avi.pool.get_server_info() | Returns the IP address and port of the server |
| avi.poolgroup.select( pool ) | Pick a specific pool group |
| avi.pool.chash( string ) | Sets the string value that the consistent hash load-balancing algorithm hashes on to choose a server within the selected pool |
| Groups | |
| avi.ipgroup.contains( ipgroup, ip-address ) | Compare an IP address against IPs within an IP Group |
| avi.stringgroup.beginswith( stringgroup, string ) | Compare a string against a list of strings within a string group |
| avi.stringgroup.contains( stringgroup, string ) | Compare a string against a list of strings within a string group |
| avi.stringgroup.equals( stringgroup, string ) | Compare a string against a list of strings within a string group |
| avi.stringgroup.endswith( stringgroup, string ) | Compare a string against a list of strings within a string group |
| SSL | |
| avi.ssl.cipher( [true] ) | Return the SSL ciphers and settings |
| avi.ssl.client_cert( [ [avi.CLIENT_CERT] [, avi.CLIENT_CERT_FINGERPRINT] [, avi.CLIENT_CERT_SUBJECT] [, avi.CLIENT_CERT_ISSUER] [, avi.CLIENT_CERT_SERIAL]] ) | Returns the client's certificate, or part of it |
| avi.ssl.protocol( ) | Return the SSL version |
| avi.ssl.server_name( ) | Return SNI name field |
| Crypto | |
| avi.crypto.decrypt( ciphertext, key [, iv [, algo]] ) | Decrypt content |
| avi.crypto.encrypt( plaintext, key [, iv [, algo]] ) | Encrypt content |
| Utilities | |
| avi.utils.base64_decode( string ) | Decode content |
| avi.utils.base64_encode( string ) | Encode content |
| avi.utils.get_geo_from_ip (ip_string, [flag]) | Used to extract geolocation database information |
| avi.utils.ip.addr (ipaddr, netmask) | Accepts an IP address and netmask and returns the network address |
| avi.utils.murmur_hash ( string ) avi.utils.sha1_hash ( string ) avi.utils.md5_hash ( string ) |
Hash content |
| avi.utils.rand_bytes( num_bytes ) | Generate cryptographically secure random bytes |
| avi.utils.get_ip_reputation(ip_addr) | Used to check IP reputation of a given IP address |
Note: Starting with Avi Vantage 17.1.10 and 17.2.3, DataScripts can hash arbitrary data using one of three functions supporting their corresponding named hashing methods: MurmurHash, SHA-1, and MD5.
For more information, refer to DataScript: avi.utils.murmur_hash (), avi.utils.sha1_hash (), avi.utils.md5_hash ().
Document Revision History
| Date | Change Summary |
|---|---|
| December 07, 2020 | Updated the content for avi.http.disable_auth(Version 20.1.3) |