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Showing content with the highest reputation on 02/28/2023 in Posts

  1. How to overcome this error? By doing what the error messages says.
    1 point
  2. What is it they say about the last 10% of a project is 90% of the work? I stand by my original statement "What a crappy, poorly thought-out protocol" So. Like I said earlier, 1/2 the state is in the client and 1/2 in the server. I'll add now "they have to agree". So what if they don't agree? Well, here we go. Client and server maintain a list of packets (Packet Identifier). Ok. Can do that. OK. But what if I don't get the PUBREC? I can send a duplicate right? Sweet Oh wait. Ok So we save them up for connect only. Job done, right? Ummm. So we can only send duplicates at connect (and only if it's a persistent session) and there can only be so many unacknowledged ACK's otherwise we get spanked. So what happens if the unacknowledged packets reaches the limit? Really? Go silent or hope for the best depending on the whim of the developer? Hmmm. So what does this look like in the real world. EMQX: 2 hours before getting Receive Maximum exceeded. Hive: 20 minutes before getting Receive Maximum exceeded. Mosquitto: 1 hour before getting Receive Maximum exceeded. That's no good. Lets send duplicates if we have some acks and are getting near the limit (that's what we should be doing IMHO) EMQX: 40 minutes before getting getting disconnected (Packet Identifier in use). Can't blame them. Crappy protocol. Hive: 24 hrs and still going but getting duplicates in the subscriber (that's not right for QOS 2 but could live with it.) Mosquitto: 24 hrs. and still going. No problems. We have a winner! This is a doozy too: Fix the state (normally that would be with duplicates), restart (without persistent session-poor subscribers ) or blame someone else. Am I missing something?
    1 point
  3. Hi everyone, I was forced to insert google (or equivalent) maps in a project and, for some time, I used Mohammad Garousi version (that I found the most complete version freely available on the web). It uses the GMap.NET dlls. After some time I noticed a recurring random issue at dll level, after which a red cross appears in the .net container without any chance to correct or avoid the error. After some time I decided to create a new map container that might solve the issue. I decided to use a picture instead of the .net container. I was able to add new functions too, like creating a route, customize its behavior (such as changing the route color to spectrum), or add another image moving with map position or zoom change and so over. The result is attached below. This is a full-working example that can be studied or modified at will, but still a demo and not a library or final release. User can move map dragging it inside the picture, can zoom with the slider and so on. Coordinates and cursor positions are updated live any time the cursor is in the picture area. You can draw a route enabling the draw button. Remember to set it off when drawing is over. You can add a third party image (the default one is a drone image) in the picture 0,0 position. You can easily customize the default position acting on the block diagram code. Any time you set the image button to on, the image will be placed to the 0,0 position, recalculating its latitude-longitude coordinates. You can dynamically change map representation, route color or zoom. I hope this example can be useful for those who need a more stable GIS representation. If any issues are discovered, please contact me. Bye Flavio LabGIS.rar
    1 point
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