I switched mhttpd to use the new javascript based run start and stop pages.

There are two new html pages:

resources/start.html - mimics the old run start page exactly - where you can enter the "edit on 
start" parameters and start the run.
resources/transition.html - monitors the transition progress, shows the status of every transition 
client, their sequence number, waiting list dependency, time spent making rpc calls, etc.

If the new pages do not work for you, please report it here and switch to the old pages
by editing src/mhttpd.cxx - comment-out the line "#define NEW_START_STOP 1"

K.O.

> Hello, 
> I'm trying to make Wiener PCIVME link work with MIDAS. 
> In documentation/VME dirvers/ it's saying: "wevmemm.c PCI/VME Wiener board
> supported. (see Wiener PCI)".
> Provided link is dead. Does anyone have that file? I would appreciate very very
> much if someone could send it to me.
> 
> Thank you and best regards, 
> L.P.

Hi, I am not familiar with this module, I am pretty sure I have never seen one.
I do not see any code for it in the midas distribution.
I do not see any reference to it on the wiener web site (http://www.wiener-d.com/)

For obsolete modules, they direct us to http://file.wiener-d.com/ which is dead.

The next best step is to contact Wiener customer support. They usually reply very quickly.

If you have no luck getting answer directly from Wiener, you can ask me to contact them through
our sales representative. He is always super very helpful.

K.O.

Hello, 
I'm trying to make Wiener PCIVME link work with MIDAS. 
In documentation/VME dirvers/ it's saying: "wevmemm.c PCI/VME Wiener board
supported. (see Wiener PCI)".
Provided link is dead. Does anyone have that file? I would appreciate very very
much if someone could send it to me.

Thank you and best regards, 
L.P.

odbinit is a new utility program to initialize new ODB and to recover from corrupted ODB.

Right now, midas odb has some strange properties different from typical behavior of other 
database packages:

a) a new odb of default size is automatically create run running *any* midas program (surprise: now 
way to specify the size of odb).
b) the size of ODB is not saved anywhere. If your experiment requires an ODB of big size, one 
always forgets to use "odbedit -s" when recovering from odb corruption, leading to massive 
confusion: nothing works, odb is corrupted? (maybe not), recreate odb (of default size instead of 
large size), reload odb, (reload fails, odb is too small), now really for sure nothing works. Been 
there, done that myself 100 times. Tired.
c) there is no midas tool to automatically recover from odb corruption (or any generic ODB 
malfunction, such as stuck ODB semaphore): shared memory has to be deleted, old .ODB.SHM 
has to be deleted, old semaphore has to be deleted. Some of these steps are different on Linux 
and MacOS (hello Apple, where is MacOS "ls -l /dev/shm"?!?).

The new odbinit tool corrects these problems:

1) ODB size is saved to .ODB_SIZE.TXT, then is used to recreate ODB after corruption recovery
2) "odbinit -s different_size_from_saved_size" will ask "are you sure?". No way to unintentionally 
change size of ODB.
3) if you already have an ODB, it will insist that you say "odbinit --cleanup"
4) there is a "-n" mode, to report what will be done, but "do nothing"
5) "odbinit --cleanup" tries very hard to recover from any and all possible ODB problems.
6) old .ODB.SHM is never deleted, always renamed to .ODB.SHM.timestamp
7) if "odbinit" gets to "Done!", you have a working ODB, 100% guaranteed, for sure.
8) output of "odbinit" is very verbose for pasting into this forum here to make it possible to debug 
your problem. (in the unlikely case odbinit fails).

Next step will be to remove the automatic creation of ODB (and event buffers) and require running 
"odbinit" to create a new experiment. ("odbedit -s nnn" will be removed).

But not today, as all that requires changes to the midas internal APIs: ss_shm_open() needs to 
return the size of connected shared memory, there needs to be ss_shm_create() and 
db_create_database(), etc.

This will make ODB to work more like a normal database: with a tool to create a new database and 
a tool to recover from corruption/malfunction.

K.O.

Confirmed, this is a bug in mlogger. It should be creating *2* files, one with the before-compression checksum and one with the after-compression checksum. At 
least both checksums are written to midas.log, so you can grep them from there. K.O.

> Hi
> 
> > On one side, such checksums help me confirm that uncompressed data contents is the same as original 
> > data (compression/decompression is okey).
> > 
> 
> > I can write the computed checksums into midas.log, or into runNNN.crc32, runNNN.sha256, etc files. (or 
> > both).
> > 
> 
> Just a thought on my side. I have been using a checksum, on data produced  by our experiments via mlogger, the runxxxx.mid.gz, in 
> the same manner you proposed and I see now implemented. 
> 
> I have a slight, objection, if I may call it that, to how the checksum is saved to disk, in 
> run00007.mid.gz.sha256 as an example.
> 
> 
> $ cat ~/Data/run00007.mid.gz.sha256
> f315af7caf6ca204cc082132862cb4227d77066cb60c6e2b1039d6dc5b04d1ee 650597 Data/run00007.mid.gz
> 
> 
> It seems a little misleading to have the gzip'd filename paired with the checksum of the uncompressed content.
> 
> May I suggest that the pairing should be ,
> 
> f315af7caf6ca204cc082132862cb4227d77066cb60c6e2b1039d6dc5b04d1ee  run00007.mid as an example.
> 
> As I find, this information will sit in an archive, database in my case for a long period, and it might
> be confusing later on, when verification of the checksum is required.

Hi

> On one side, such checksums help me confirm that uncompressed data contents is the same as original 
> data (compression/decompression is okey).
> 

> I can write the computed checksums into midas.log, or into runNNN.crc32, runNNN.sha256, etc files. (or 
> both).
> 

Just a thought on my side. I have been using a checksum, on data produced  by our experiments via mlogger, the runxxxx.mid.gz, in 
the same manner you proposed and I see now implemented. 

I have a slight, objection, if I may call it that, to how the checksum is saved to disk, in 
run00007.mid.gz.sha256 as an example.


$ cat ~/Data/run00007.mid.gz.sha256
f315af7caf6ca204cc082132862cb4227d77066cb60c6e2b1039d6dc5b04d1ee 650597 Data/run00007.mid.gz


It seems a little misleading to have the gzip'd filename paired with the checksum of the uncompressed content.

May I suggest that the pairing should be ,

f315af7caf6ca204cc082132862cb4227d77066cb60c6e2b1039d6dc5b04d1ee  run00007.mid as an example.

As I find, this information will sit in an archive, database in my case for a long period, and it might
be confusing later on, when verification of the checksum is required.

> 
> More suggestions from John and my reply.
> 
> > we also don't use the VME back plane - it's just too slow - mixing VME commands to plain modules and digitizer modules is unreliable....
> 
> > We use CAEN fiberoptic version 2 to talk to the digitizers directly, we have upto 12 digitizers, and can use all channels for several hours, and can fill to about 75% 
> of the A3818 bandwidth... 
> 
> So far we are limitted to 30 MB/s, if tested with CAEN examples, for example, the wavedump program by CAEN.
> I think is kind of the limit by IDE hard drive.
> Unfortunately we are still far from that limit, only ~ 1 MB/s now.  :(
>

From writing MIDAS frontends for many years, I am starting to form an opinion that this type of problem is undebuggable
in the current midas frontend framework - it is impossible to separate problems in vendor-supplied libraries and linux kernel modules
from problems with midas (i.e. incorrectly created data banks, too-small event buffers getting full) from problems with
bad interaction (collision over the SIGALARM handlers).

I am pondering on a new scheme for midas frontend writing. Perhaps such a new scheme should have a "no midas" mode where you can
compile and link a midas frontend "without midas", leaving you to debug just your code and the vendor code and their interactions.

K.O.

> > Midas has a nice alarm system. I am wondering whether it is easily possible to
> > get the Alarm/Warning banner also on top of custom pages?!
> 
> K.O. made nice JavaScript routines to access the alarm status. The new alarm page is completely 
> made dynamically from JavaScript code (mhttpd does not supply any HTML code any more, only 
> functions to obtain ODB values etc). Part of this new dynamic page must be some code to display 
> the alarm status. You just need to copy this to your custom page. K.O. can tell you details.
> 

Yes, please look at resources/alarm.html and the "get_alarms" JSON-RPC method. The "get_alarms" example in 
resources/example.html probably already does exactly what you need. Also note the presence of "al_reset_alarm" and 
"al_trigger_alarm" JSON_RPC methods.

K.O.

> Hi. Is it currently possible to automatically save the MIDAS ODB as a JSON file?
> I can do it manually in odbedit, but it looks like the only option for the
> automatic ODB save for each run is the standard .ODB format. Is there a way to
> change this?

I think today it makes sense to make all ODB dump in the JSON format - in my experience it is much 
easier to work with JSON data compared to XML data.

To write the ODB dump file in JSON format, set "/logger/ODB Dump File" to "run%05d.json".

In the midas data files, the ODB dump made into the begin-of-run and end-of-run events is presently 
unconditionally done in XML format.

Perhaps the data file dump should match the format of the odb dump file (both XML or both JSON or 
both ODB).

But at the moment our standard analyzer ROOTANA does not have the code to process JSON ODB 
dumps, so I am hesitant to make this change today, Maybe tomorrow when there is a VirtualODB 
JsonOdb class in ROOTANA. The requires JSON parser is already part of MIDAS (mjson.h/mjson.cxx).

K.O.

> I've recently run into issues when using JSON.parse on ODB keys containing 
> 8-bit data.

I am tempted to take a hard line and say that in general MIDAS TID_STRING data should be valid 
UTF-8 encoded Unicode. In the modern mixed javascript/json/whatever environment I think
it is impractical to handle or permit invalid UTF-8 strings.

Certainly in the general case, replacing all control characters with something else or escaping them or 
otherwise changing the value if TID_STRING data would wreck *valid* UTF-8 strings, which I would 
assume to be the normal use.

In other words, non-UTF-8 strings are following non-IEEE-754 floating point values into oblivion - as 
we do not check the TID_FLOAT and TID_DOUBLE is valid IEEE-754 values, we should not check 
that TID_STRING is valid UTF-8.

But in your specific case, why do you have random control characters in your TID_STRING data? 
Maybe you are using TID_STRING as general storage instead of arrays of TID_CHAR or 
TID_DWORD?

K.O.



> 
> For JSON.parse to successfully parse a string, (A) the string must be valid 
> UTF-8, (B) several whitespace characters, control characters, and the 
> characters " and \ must be escaped, and (C) you've got to follow the key-
> value rules laid out in http://www.json.org/.
> 
> The web browser takes care of (A), and I verified that for this key Midas 
> handled (C) correctly.  In principle, the function json_write in odb.c 
> handles (B) - but json_write does not escape control characters.
> 
> To manage this problem, I modified json_write (in odb.c) to replace any 
> control character with the more-inocuous character, 'C'.  My default case 
> now looks like:
> 
> default:
>          {
>            // if a char is a control character,
>            // print 'C' in its place
>            // note that this loses data:
>            // a more-correct method would be to print
>            // \uXXXX, where XXXX is the character in hex
>            if(iscntrl(*s)){
>              (*buffer)[(*buffer_end)++] = 'C';
>              s++;
>            } else {
>              (*buffer)[(*buffer_end)++] = *s++;
>            }
>          }
>       
> Where the call to iscntrl(*s) requires the addition of the ctype.h header 
> file.
> 
> I'm guessing a blanket replacement of control characters with 'C' isn't 
> something all Midas users would want to do.  Replacing the control character 
> with its hex value seems like a good choice - but not without adding bounds 
> checking!
> 
> An alternative to changing odb.c could be to add a regex to Midas response 
> text which removes all control characters (U+0000 - U+001F): 
> 
> var resp_lint = req.response.replace(/[\u{0000}-\u{001F}]/gmu, '');
> var json_obj = JSON.parse(resp_lint);
> 
> Unfortunately, the 'u' regex flax doesn't work on the Firefox version 
> included in Scientific Linux 6.8.  

> I recently needed to watch the Midas messages for a particular error - and 
> thus needed a command to "get all the messages since a time t".
> 
> The documentation (https://midas.triumf.ca/MidasWiki/index.php/AJAX#jmsg) 
> documents a way to "get the most recent n messages" - but when I dug into the 
> code, I was delighted to find that the existing Midas code also supports the 
> "get all messages since t" query.
> 
> For the "get all messages since t" query, the parameter t should be the unix 
> timestamp in seconds, and the parameter n should be zero: curl -X GET 
> "http://localhost:8081/?cmd=jmsg&n=0&t=1473437918".
> 
> Pretty useful!  Perhaps this should be added to the AJAX documentation?

The "jmsg" methods are obsolete - please use the JSON-RPC method "cm_msg_retrieve" as shown in resources/example.html. It takes all the same parameters as the midas.h 
cm_msg_retrieve() function, see the snipped from example.html below.

To see the full list of JSON-RPC methods, go to the "help" page and press the button for "json-rpc schema in text table format".

The entry for "cm_msg_retrieve" has this:

------------------------------------------------------------------------------------
cm_msg_retrieve?      | Retrieve midas messages using cm_msg_retrieve2()
                      | ------------------------------------------------------------
                      | params   | facility?           | string         | message facility, default is "midas"
                      |          | min_messages?       | integer        | get at least this many messages, default is 1
                      |          | time?               | number         | start from given timestamp, value 0 means give me newest messages, default is 0
                      | ------------------------------------------------------------
                      | result   | num_messages        | integer        | number of messages returned
                      |          | messages            | string         | messages separated by \n
                      |          | status              | integer        | return status of cm_msg_retrieve2()
------------------------------------------------------------------------------------

Snippet from resources/example.html: (to add "time" parameter, put "time":12345 next to "min_messages").

<input type=button value='Get last 10 midas messages'
          onClick='mjsonrpc_call("cm_msg_retrieve", { "min_messages": 10 })
                   .then(function(rpc) {
                   document.getElementById("cm_msg_retrieve_num_messages").innerHTML = JSON.stringify(rpc.result.num_messages);
                   document.getElementById("cm_msg_retrieve_messages").innerHTML = JSON.stringify(rpc.result.messages);
                   //mjsonrpc_debug_alert(rpc);
                   })
                   .catch(function(error) {
                   mjsonrpc_error_alert(error);
                   });'></input>

> Since updating to the most recent midas commit, we get the following error if we try running mhttpd without su privileges: 
> 
> >mhttpd -e CR --http 8081
> mhttpd is running in setuid-root mode.
> mhttpd is listening on port 80
> Mongoose version 4 cannot listen to port 80 in setuid mode. Please use mongoose version 6. Sorry, bye!
> [mhttpd,ERROR] [midas.c:1960:,ERROR] cm_disconnect_experiment not called at end of program
> 
> It works if we run it as root, but that creates other problems. Is there a flag to turn off setuid-root mode? Or some other fix?
> 


From these messages, it looks like you really are using the setuid-root mode. And indeed it is not usable with the mongoose version 4 implementation in MIDAS.

I can suggest several fixes:

1) the setuid-root mode was only ever intended for use at PSI because of peculiar network configuration of the PSI corporate firewall. It is not intended for general 
use.
1a) I as an author of MIDAS recommend against using the setuid-root mode and against installing mhttpd as setuid-root because it is not secure. (normally you 
would run mhttpd behind an apache https proxy providing https encryption and password protection).
1b) if you follow the midas installation instructions at https://midas.triumf.a you will see that we do not login as root and run "make install" to install mhttpd as 
setuid-root.
1c) if you follow these instructions, or if you run mhttpd from the midas build directory ($MIDASSYS/linux/bin/mhttpd), the setuid-root mode will not activate and 
everything will work ok.

2) you can run in the "old server" mode, but this more does not implement the JSON-RPC methods, so the "programs" and "alarms" pages will not work.
3) you can build mhttpd with the mongoose version 6 implementation, it will work even with the setuid-root mode. To do this, edit the Makefile, comment-out 
"USE_MONGOOSE4=1" and uncomment "USE_MONGOOSE6=1", then make clean, make.

K.O.

Since updating to the most recent midas commit, we get the following error if we try running mhttpd without su privileges: 

>mhttpd -e CR --http 8081
mhttpd is running in setuid-root mode.
mhttpd is listening on port 80
Mongoose version 4 cannot listen to port 80 in setuid mode. Please use mongoose version 6. Sorry, bye!
[mhttpd,ERROR] [midas.c:1960:,ERROR] cm_disconnect_experiment not called at end of program

It works if we run it as root, but that creates other problems. Is there a flag to turn off setuid-root mode? Or some other fix?

Thanks,
Wes

> We have started a new elog for discussions of the ROOTANA MIDAS analyzer package

Posting there is almost like talking to oneself - barely anybody is subscribed, not even me.

Hence this reminder.

If you use ROOTANA, click the "config" link, then click the "rootana" checkbutton, then "save".

K.O.

> latest version of mongoose web server library (v6.4) is now implemented in midas.

A number of bugs were found in the mongoose v6 implementation of HTTP digest authentication:

- unusual URL in the form "https://blah:8443/?" (notice trailing "?") were rejected. These URLs are sometimes generated by 
MIDAS.
- URLs longer than 200 bytes were rejected
- a check for matching URIs between the HTTP request and in digest authentication was missing (required by specs)

If you are using mhttpd with mongoose v6 https, please update mhttpd.cxx to the latest version.

We continue to recommend that mhttpd be used behind a proper HTTPS proxy with password protection (i.e. apache httpd).

mongoose v4 does not seem to have the same bugs, old server does not support https so does not have these bugs.

K.O.

> I recently needed to watch the Midas messages for a particular error - and 
> thus needed a command to "get all the messages since a time t".
> 
> The documentation (https://midas.triumf.ca/MidasWiki/index.php/AJAX#jmsg) 
> documents a way to "get the most recent n messages" - but when I dug into the 
> code, I was delighted to find that the existing Midas code also supports the 
> "get all messages since t" query.
> 
> For the "get all messages since t" query, the parameter t should be the unix 
> timestamp in seconds, and the parameter n should be zero: curl -X GET 
> "http://localhost:8081/?cmd=jmsg&n=0&t=1473437918".
> 
> Pretty useful!  Perhaps this should be added to the AJAX documentation?

Thank you - I have added it to the documentation.

I recently needed to watch the Midas messages for a particular error - and 
thus needed a command to "get all the messages since a time t".

The documentation (https://midas.triumf.ca/MidasWiki/index.php/AJAX#jmsg) 
documents a way to "get the most recent n messages" - but when I dug into the 
code, I was delighted to find that the existing Midas code also supports the 
"get all messages since t" query.

For the "get all messages since t" query, the parameter t should be the unix 
timestamp in seconds, and the parameter n should be zero: curl -X GET 
"http://localhost:8081/?cmd=jmsg&n=0&t=1473437918".

Pretty useful!  Perhaps this should be added to the AJAX documentation?

I've recently run into issues when using JSON.parse on ODB keys containing 
8-bit data.

For JSON.parse to successfully parse a string, (A) the string must be valid 
UTF-8, (B) several whitespace characters, control characters, and the 
characters " and \ must be escaped, and (C) you've got to follow the key-
value rules laid out in http://www.json.org/.

The web browser takes care of (A), and I verified that for this key Midas 
handled (C) correctly.  In principle, the function json_write in odb.c 
handles (B) - but json_write does not escape control characters.

To manage this problem, I modified json_write (in odb.c) to replace any 
control character with the more-inocuous character, 'C'.  My default case 
now looks like:

default:
         {
           // if a char is a control character,
           // print 'C' in its place
           // note that this loses data:
           // a more-correct method would be to print
           // \uXXXX, where XXXX is the character in hex
           if(iscntrl(*s)){
             (*buffer)[(*buffer_end)++] = 'C';
             s++;
           } else {
             (*buffer)[(*buffer_end)++] = *s++;
           }
         }
      
Where the call to iscntrl(*s) requires the addition of the ctype.h header 
file.

I'm guessing a blanket replacement of control characters with 'C' isn't 
something all Midas users would want to do.  Replacing the control character 
with its hex value seems like a good choice - but not without adding bounds 
checking!

An alternative to changing odb.c could be to add a regex to Midas response 
text which removes all control characters (U+0000 - U+001F): 

var resp_lint = req.response.replace(/[\u{0000}-\u{001F}]/gmu, '');
var json_obj = JSON.parse(resp_lint);

Unfortunately, the 'u' regex flax doesn't work on the Firefox version 
included in Scientific Linux 6.8.  

Hi,
We do generate a .json odb at the end of run in order to extract some of its info for our CouchDB.
This is done using the "/program/Execute on stop run" script command. This method decouples the necessity 
to describe completely the info extraction within the ODB/Logger/"CouchDB" and provides possibly better 
flexibility. But including a CouchDB support in the logger as well (like SQL) would be nice too.

Pierre-André


> > Hi. Is it currently possible to automatically save the MIDAS ODB as a JSON file?
> > I can do it manually in odbedit, but it looks like the only option for the
> > automatic ODB save for each run is the standard .ODB format. Is there a way to
> > change this?
> 
> You mean you like an ODB dump at the end of every run in JSON format?
> 
> Sure this can be implemented. But I wonder for what purpose you need that. Can you elaborate a 
> bit, maybe it's a useful feature also other people should be aware of. I'm also thinking if we should 
> offer a CouchDB interface, so ODB data is written directly to that database.
> 
> Stefan

> Hi. Is it currently possible to automatically save the MIDAS ODB as a JSON file?
> I can do it manually in odbedit, but it looks like the only option for the
> automatic ODB save for each run is the standard .ODB format. Is there a way to
> change this?

You mean you like an ODB dump at the end of every run in JSON format?

Sure this can be implemented. But I wonder for what purpose you need that. Can you elaborate a 
bit, maybe it's a useful feature also other people should be aware of. I'm also thinking if we should 
offer a CouchDB interface, so ODB data is written directly to that database.

Stefan