We have some computers that don't have an OLE DB driver that some other computers rely on for a central shared spreadsheet to update - it's becoming quite limiting that only a few users can update the sheet when others need it to be up to date.
The driver is called 'ACT OLE DB Provider for Reporting 2.0'. I have googled online for it and can't find a download link anywhere so I think it must come with the program; however all computers involved are using the most up-to-date version of ACT despite only some having the driver.
How can I manually copy the driver from one computer to others?
ACT! seems to be some sort of CRM Marketing service and the provider is part of their SDK. Just a short google gave me...
How to Create an OLE DB 2.0 Connection in Act!
Which links to...
How to download the Act! Software Development Kit
I may have the wrong thing entirely of course. Is this what you are looking for?
Related
If I am to make an online backup using the neo4j-admin backup tool remotely, as is advised by Neo4J, I have to open a public IP and the backup port on my Neo4J application.
However, I don't see neo4j-admin asking for any login credentials, basically making it possible for anybody to access the server and copy all the data while the port is opened.
There is no setting inside the neo4j.conf that would only accept backup requests from a certain address.
So what does it mean? When the online backups are done remotely, as is advised, the database may be vulnerable to somebody else just copying all the data.
I didn't find anything in Neo4J documentation that addresses this flaw (only a warning) and it looks like in more than 7 years that this feature has been available as a part of the commercial enterprise version there has not been any solution offered for this.
What do you do to protect the DB then? At the moment the only solution seems to not back it up remotely, but that causes additional stress on the server and is not the best solution. Plus the online backup is not stable when done locally for large DBs. Another solution could be to only open the port remotely via some kind of API to the server, but that may still be exploited if somebody figures out the time frame when the backup is made.
The documentation states that ne04j-admin must be invoked as the neo4j user. That is the user that owns the neo4j executables and the databases. So the security is handled by the OS login and the file permissions should be set to prevent unathorised access to the neo4j directories/files including the neo4j-admin executable.
I'm developing an application that is able to determine which application using internet. Now my problem is that i want to know the process name before it successfully establish connection much like a firewall.
I'm using Delphi2009. So the suggestions in that technology are appreciated.
Look at Winsock Layered Service Providers to monitor traffic. I believe LSPs are DLLs that get loaded into each process, so you should be able to call GetModuleFileName(NULL) to discover the EXE name when your DLL is loaded.
The Wikipedia article linked above shares my strongest concerns:
One major common issue with LSPs was that if they were to be removed
or unregistered improperly or if the LSP was buggy, it would result in
corruption of the Winsock catalog in the registry, and the entire
TCP/IP stack would break and the computer could no longer access the
network.
So if you are new to Windows programming and/or do not take proper precautions with writing these types of filter drives, then tread carefully. Otherwise, a bug in your program will easily screw up the user's machine.
Has somebody real experience with firebird databases over the internet?
I have a typical windows accounting/ERP software (done with delphi) that works with the firebird database server pretty well.. Now my users (300 aprox. now, but should increment) also want to work "in the cloud" (connecting from the office, from the laptop, from the house, etc.). It is a lot of work of recreating everything to a standard web application (let's say for example, HTML+CSS+JS+PHP+MYSQL), so I'm considering keeping the win client (I don't care about other OSes) but instead of the server living in the clients LANs moving it to a pair of dedicated servers that I will contract (one primary and one secondary againts failures for starting).
Searching I've come across this faq http://www.firebirdfaq.org/faq53/ that explains that the fb protocol it isn't ideal for working in the internet, but still all my users today have at least a 1MBbit/sec ADSL internet connection (I don't think that to be slow as the faq denotes).
Somebody have done this? what was the experience? how secure are fb servers for being open to the internet? how well they scale?
I know that building a "middleware" with SOAP for example will be more normal, but still the solution I'm evaluating here is much more fast and easy (still I have some work with the replication, backup, hearbreath services, but it's much less than redoing everything for the web).
Thanks! Edit: FB version: 2.5.
I had being trying to "push" the Firebird Core developers to improve the Firebird protocol to get better speed with high latency network (aka. Internet). Recently, Dmitry Yemanov published some articles in his blog about this subject (dyemanov.blogspot.com). It seems that there is margin for optimizations, and I would really like to see this coming in FB 2.5.3 and FB 3.0, although there is no warranty for this happening in those versions or anytime soon. You can vote in such improvement here: http://tracker.firebirdsql.org/browse/CORE-2530
Safety? You may try to set up a VPN. It also may help with speed, since most of the VPNs software out there (Zebedee, etc) can compress the data being transfered, helping to speed up data transfer in some cases.
Some of my customers do use Firebird traditional C/S over the internet. It is much slower compared to local network, and of course, how much slower depends basically on the link speed and latency. You can do some optimization at the client side too, using metadata cache, etc. but don't expect miracles with the currently protocol. I would say that for whole day working, using Terminal Services would be a better option for now.
The response about the scaling question
Firebird runs in production on large big iron servers : 512G of ram 100.000 concurrent users
We run Firebird to power larger systems (for 12 government agencies
and 3 banks). It has approximately 100000 end users multiplexed
through 2500 (max) pooled connections
https://plus.google.com/111558763769231855886/posts/Q1ACy1yyTgP
The protocol in Firebird 2.5 is improoved there is still room left for 3.0 but you can check
what is already done
http://asfernandes.blogspot.com/2009/07/network-latency-influence-on-firebird.html
And the future enhancements in 3.0
http://www.firebirdnews.org/?p=6953
To protect your connection i guess the best bet is ssl/ssh tunnel (it can be a opnvpn)
with high compression option
http://mapopa.blogspot.com/2010/11/securing-firebird-using-ssh-tunnel.html
FB protocol problem isn't about bandwidth, but latency. In my experience, some operations can be very slow over internet/VPN compared to LAN or local connection. I haven't examined issue further since I don't really run applications over internet connection.
However, I suggest three-tier model for application. Create own application server, which runs on database server/same network. Let the clients talk with application server and you get maximum performance.
There are some N-tier application/middleware frameworks for Delphi:
RemObjects SDK and DataAbstract
RealThinClient
kbmMW
Delphi's own DataSnap
MidWare
With those you can get data compression, encryption, binary messages (faster than SOAP) etc.
You can implement TCP/IP packets encryption/decryption directly in the firebird engine itself.
Personnaly, i have downloaded the Firebird 2.5 source code and injected secure tunnelization code directly in his low level communication layer (the INET socket layer). Now, encryption/decryption is done directly by the firebird engine for each TCP/IP packet both at the server side and the client side (fbclient.dll).
Then there is no need to re-structure the client application except adding one line of code that provide the secret key you choose to crypt communication to the fbclient.dll. The same secret key must be declared in the firebird.conf file of your server installation.
I have also implemented a proxy negociation solution in the fbclient.dll in order to allow to TCP/IP packets to pass throught any proxy server (like Microsoft ISA Server for example).
For us, this architecture is functional for more than one year in a real production system.
kbmMW CodeGear Edition is free but without source. It can be used for commercial apps.
Download it after registering at: https://portal.components4developers.com
In case you see certificate errors (you shouldnt but I know we have heard that some actually do), accept and ignore them. The site is valid despite the cert.error.
kbmMW CodeGear Edition contains a subset of kbmMW Professional Edition, but supports the following Delphi database API's:
Borland Database Engine
DBExpress
kbmMemTable
SQLite3
It supports binary, binary over HTML, XML and SOAP protocols in communication with clients.
It contains everything you need incl.
unified remote custom method invocation
unified remote dataset query, execute and data change resolving
unified database meta data handling and creation (tables, fields, indexes, generators/sequencers)
optional automatic proxying of requests to another server and proxying results back to original requester
full native XML DOM and SAX support
full dataset briefcase support as CSV, or binary data
advanced but simple to use wizard for creating new application server services
THere is one caveat though. Newest version of kbmMW CodeGear Edition always only supports newest Delphi version. You can still download older kbmMW CodeGear Editions matching older Delphi releases.
kbMMW Professional Edition and kbmMW Enterprise Edition do not have such limitations, and currently supports D7, D2006, D2007, D2010, DXE, DXE2 along with Embarcadero C++ counterparts.
best regards
Kim Madsen
www.components4developers.com
I want to know which is the best architecture to adopt for this case :
I have many shops that connect to a web application developed using Ruby on Rails.
internet is not reachable all the time
The solution was to develop an offline system which requires installing a local copy of the distant database.
All this wad already developed.
Now what I want to do :
Work always on the local copy of the database.
Any change on the local database should be synchronized with distant database.
All the local copies should have the same data in other local copies.
To resolve this problem I thought about using a JMS like software eventually Rabbit MQ.
This consists on pushing any sql request into a JMS queue that will be executed on the distant instance of the application which will insert into the distant DB and push the insert or SQL statement into another queue that will be read by all the local instances. This seems complicated and should slow down the application.
Is there a design or recommendation that I must apply to resolve this kind of problem ?
You can do that but essentially you are developing your own replication engine. Those things can be a bit tricky to get right (what happens if m1 and m3 are executed on replica r1, but m2 isn't?) I wouldn't want to develop something like that unless you are sure you have the resources to make it work.
I would look into existing off-the shelf replication solution. If you are already using a SQL DB it probably has some support for it. Look here for more details if you are using MySQL
Alternatively, if you are willing to explore other backends, I heard that CouchDB has great support for replication. I also heard of people using git libraries to do that sort of thing.
Update: After your comment, I realize you already use MySql replication and are looking for solution for re-syncing the databases after being offline.
Even in that case RabbitMQ doesn't help you at all since it requires constant connection to work, so you are back to square one. Easiest solution would be to just write all the changes (SQL commands) into a text file at a remote location, then when you get connection back copy that file (scp, ftp, emaill or whatever) to master server, run all the commands there and then just resync all the replicas.
Depending on your specific project you may also need to make sure there are no conflicts when running commands from different remote location but there is no general technical solution to this. Again, depending on the project, you may want to cancel one of the transactions, notify the users that it happened and so on.
I would recommend taking a look at CouchDB. It's a non-SQL database that does exactly what you are describing automatically. It's used especially in phone applications that often don't have internet or data connectivity. The idea is that you have a local copy of a CouchDB database and one or more remote CouchDB databases. The CouchDB server then takes care of teh replication of the distributed systems and you always work off your local database. This approach is nice because you don't have to build your own distributed replication engine. For more details I would take a look at the 'Distributed Updates and Replication' section of their documentation.
The situation is simple. I've created a complex Delphi application which uses several different techniques. The main application is a WIN32 module but a few parts are developed as .NET assemblies. It also communicates with a web service or retrieves data from a specific website. It keeps most of it's user-data inside an MS Access database with some additional settings inside the Registry. In-memory, all data is converted inside an XML document, which is occasionally saved to disk as backup in case the system crashes. (Thus allowing the user to recover his data.) There's also some data in XML files for read-only purposes. The application also executes other applications and wants for those to finish. All in al, it's a pretty complex application.
We don't support Citrix with this application, although a few users do use this application on a Citrix server. (Basically, it allows those users to be more mobile.) But even though we keep telling them that we don't support Citrix, those customers are trying to push us to help them with some occasional problems that they tend to have.
The main problem seems to be an occasional random exception that seems to pop up on Citrix systems. Never at the same location and often it looks related to some memory problems. We've p[lenty of error reports already and there are just too many different errors. So I know solving all those will be complex.
So I would like to go a bit more generic and just want to know about the possible issues a Delphi (2007) can have when it's run on a Citrix system. Especially when this application is not designed to be Citrix-aware in any way. We don't want to support Citrix officially but it would be nice if we can help those customers. Not that they're going to pay us more, but still...
So does anyone know some common issues a Delphi application can have on a Citrix system?
Does anyone know about common issues with Citrix in general?
Is there some Silver Bullet or Golden Hammer solution somewhere for Citrix problems?
Btw. My knowledge about Citrix is limited to this Wikipedia entry and this website... And a bit I've Googled...
There were some issues in the past with Published Delphi Applications on Citrix having no icon in the taskbar. I think this was resolved by the MainFormOnTaskbar (available in D2007 and higher). Apart from that there's not much difference between Terminal Server and Citrix (from the Application's perspective), the most important things you need to account for are:
Users are NEVER administrator on a Terminal or Citrix Server, so they no rights in the Local Machine part of the registry, the C drive, Program Folder and so on.
It must be possible for multiple users on the same system to start your application concurrently.
Certain folders such as the Windows folder are redirected to prevent possible application issues, this is also means that API's like GetWindowsFolder do not return the real windows folder but the redirected one. Note that this behaviour can be disabled by setting a particular flag in the PE header (see delphi-and-terminal-server-aware).
Sometimes multiple servers are used in a farm which means your application can run on any of these servers, the user is redirected to the least busy server at login (load balancing). Thefore do not use any local database to store things.
If you use an external database or middleware or application server note that multiple users will connect with the same computername and ip address (certain Citrix versions can use Virtual IP addresses to address this).
Many of our customers use our Delphi applications on Citrix. Generally speaking, it works fine. We had printing problems with older versions of Delphi, but this was fixed in a more recent version of Delphi (certainly more recent than Delphi 2007). However, because you are now running under terminal services, there are certain things which will not work, with or without Citrix. For example, you cannot make a local connection to older versions of InterBase, which use a named pipe without the GLOBAL modifier. Using DoubleBuffered would also be a really bad idea. And so on. My suggestion is to look for advice concerning Win32 apps and Terminal Services, rather than looking for advice on Delphi and Citrix in particular. The one issue which is particular to Citrix that I'm aware of is that you can't count on having a C drive available. Hopefully you haven't hard-coded any drive letters into your code, but if you have you can get in trouble.
Generally speaking, your application needs to be compatible with MS Terminal Services in order to work with XenApp. My understanding is that .NET applications are Terminal Services-compatible, and so by extension should also work in a Citrix environment. Obviously, as you're suffering some problems, it's not quite that simple, however.
There's a testing and verification kit available from http://community.citrix.com/citrixready that you may find helpful. I would imagine the Test Kit and Virtual Lab tools will be of most use to you. The kit is free to use, but requires sign-up.
Security can be an issue. If sensitive folders are not "sandboxed" (See Remko's discussion about redirection), the user can break out of your app and run things that they shouldn't. You should probe your app to see what happens when they "shell out" of your app. Common attack points are CHM Help, any content that uses IE to display HTML, and File Open/Save dialogs.
ex: If you show .chm help, the user can right-click within a help topic, View Source. That typically opens Notepad. From there, they can navigate the directory structure. If they are not properly contained, they may be able to do some mischief.
ex: If they normally don't have a way to run Internet Explorer, and your app has a clickable URL in the about box or a "visit our web site" in the Help menu, voila! they have access to the web browser. If unrestrained, they can open a command shell by navigating to the windows directory.