The Wiert Corner – irregular stream of stuff

The RouterOS scripting language you can use on Mikrotik device immediately shows it’s origin: the console.

• It is a statement oriented language where statement separators can be both semicolons and new-lines.
• You can use the \ at the end-of the line as line-continuation character effectively spreading statements over multiple lines.

As promised some links to questions I asked:

• What parts of scripts can be ran from the console? – MikroTik RouterOS
  The answer teaches about scope and locality on the console.
• Difference between `[]`, `{}` and `()` expressions? – MikroTik RouterOS
  Their positioning can be tricky:
  
• Bug? How can I create an empty associative array, then fill it to map strings to strings? – MikroTik RouterOS
  This is how you do it:
  :global convert ({});
• Is there a good way to sync a local directory from the scripts that a Mikrotik has? – MikroTik RouterOS
  No there isn’t. There is a way to sync /system script entries to the file system, but due to a stupid 4096 length string export issue (causing the dreaded “failure: new contents too long” error), scripts longer than 4096 bytes will not even be written truncated. Since LUA got ditched and never re-introduced, LUA is not a workaround either and splitting into multiple files is impractical.
  This one-liner will show you length+name of all your /system script` entries:
  :foreach scriptId in [/system script find] do={ :local scriptSource [/system script get $scriptId source]; :local scriptSourceLength [:len $scriptSource];  :local scriptName [/system script get $scriptId name]; :put "$scriptSourceLength bytes: '$scriptName'" }
• a

Some questions by others that were also extremely useful:

• Functions and function parameters – MikroTik RouterOS
  new function syntax, much simpler than the old syntax in Functions in CMD Scripts – MikroTik RouterOS that hopefully someone someday will convert to the new syntax.
• Functions and function parameters – MikroTik RouterOS
  :typeof can return “nothing”
• Functions and function parameters – MikroTik RouterOS
  Fragment that adds all scripts named “Function.*” as :global functions upon system startup.
  Declare those functions when you need them, just like in the nested-function example.
• run script from terminal – MikroTik RouterOS 
  this is in fact very simple:
  it also has the benefit that the terminal does tell you on which line and column your script is wrong (Winbox does not show that during execution):
  
• [Solved] Use of externally defined global variables inside import scripts, – MikroTik RouterOS
  It’s better to pass information to functions as parameters (named parameters make code a lot more readable than positional parameters).
• Return IP Octet Function – MikroTik RouterOS
  Parses an IP octet and returns either a specific or all octets. More elaborate: Mikrotik Scripting – Function to Split an IP Address into an Array | Paper Street Online
  Note you can use bitwise operators on octets.
• How do you clear a global variable? – MikroTik RouterOS
  List all global variables using /system script environment
  Unset a variable with a play :set variableName
• Array Pop Function – MikroTik RouterOS
• Array Push Function – MikroTik RouterOS
• Basic XML/string parser function – MikroTik RouterOS
  Function getBetween(inputString, betweenStart, betweenEnd)
• Using :find command where string is not found – MikroTik RouterOS
  :if ([:len [:find "abcd" "x"]] > 0) do={:put "Found";} else={:put "Not Found";};
• Manual:Configuration Management – MikroTik Wiki
  When you upload a script over ftp and have it end with auto.rsc, then it is automatically being executed and logged. For instance a file called anything.auto.rsc will have the log written to anything.auto.log.
• I did it! Script to compute UNIX time! – MikroTik RouterOS
• Understanding scripting data types – MikroTik RouterOS
  :typeof, nil, nothing, str, :parse vs new-style functions (:parse can be faster!)
• Simple HTTP GET? – MikroTik RouterOS
  Some escaping required…
• It is not possible to exit or break a loop statement – MikroTik RouterOS so if you want to break a :for loop early, you have to recode it into a :while loop. You can :return from a function when inside a loop, but that’s not the same (for instance compare C# break versus return or Delphi break versus exit).
• :for loops are a strange beast so I will elaborate on those in a separate post.

And a few observations:

• Functions do not need to be global. The RouterOS Scripting Manual paragraph on functions shows an example with :global that works just as fine with :local

  :local myFunc do={:put "hello from function"} 
  $myFunc
   
  # output: 
  # hello from function

• a

–jeroen

When switching my DHCP to a Mikrotik CCR1009, both the AP7920 and AP7921 failed to get IP addresses. The APC7921 would look bounce between waiting and offered states like this:

The cause is the need of DHCP Option 43 (Vendor Class Identifier) specified in RFC2132 – based on [WayBack] RFC 2131 – Dynamic Host Configuration Protocol and [WayBack] RFC 1533 – DHCP Options and BOOTP Vendor Extensions – which I found first via these links:

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