Resolving system.net.openURL File Path Errors in Ignition 7.8

Where does the openURL request stop?

Follow the packet. A button or event script builds a string and hands it to system.net.openURL. That call runs in the Vision client JVM on the operator workstation, not on the Gateway. The client passes the URL to the operating system. The OS resolves it to a file on the SMB share and launches the viewer registered for the extension. A failure at any hop looks the same to the operator: nothing opens.

In the failing setup, system.file.fileExists(f) returned true for //srv-01/share/_NGB Work Orders/RS20141120-04/Attachments/VesselInventoryError.png. That proves hops 1 and 4 on the filesystem side: the client resolves srv-01, reaches the share, and can read the directory. The same code worked on 7.7 and stopped after the upgrade to 7.8 with no change to the share. The request dies at hop 2.

Check: add print fileToOpen before the call and read the client console output. Record the exact string being passed. For the original code it is file://///srv-01/share/_NGB Work Orders/..., which has five slashes and literal spaces.

Can the client machine reach the share at all?

Layer one first. Confirm the path from the workstation that runs the client, under the Windows account the operator logs in with, before you touch URL syntax. A Designer on an engineering laptop with domain-admin rights proves nothing about a locked-down HMI panel.

Check: all three pass. If fileExists returns false, fix the network path or permissions first. No URL encoding will open a file the client cannot read.

What URL string does 7.8 accept?

A URL cannot contain a literal space. URI syntax requires reserved and unsafe characters to be percent-encoded, and a space becomes %20. Ignition 7.7 tolerated the raw spaces in _NGB Work Orders. Ignition 7.8 parses the argument strictly, so the call is rejected before the OS ever sees it. The prefix also matters. In file://host/path form, srv-01 sits in the host position. A drive-letter path needs an empty host, which is written as three slashes.

Check: call a hard-coded, known-good literal from a test button on the client:

system.net.openURL('file://srv-01/share/_NGB%20Work%20Orders/RS20141120-04/Attachments/VesselInventoryError.png')

If the image opens, hops 2 through 5 work. What remains is to generate that string from any path.

How do I build the URL in script?

Put the conversion in a project script library function so every button uses one implementation. The function normalises the separators, picks the prefix, encodes the path, and logs the result.

def openNetworkFile(filePath):
    # Normalise Windows separators to forward slashes
    path = filePath.replace('\\', '/')

    # Drive letter (C:/, S:/) -> file:///   UNC (//server/share) -> file:
    if ':' in path:
        prefix = 'file:///'
    else:
        prefix = 'file:'

    # Encode '%' first so later escapes are not double-encoded,
    # then '#' (fragment marker) and spaces
    path = path.replace('%', '%25').replace('#', '%23').replace(' ', '%20')

    url = prefix + path
    print url
    system.net.openURL(url)

Call it from the button with the raw path. Keep the existence test on the unencoded filesystem path:

f = '//srv-01/share/_NGB Work Orders/RS20141120-04/Attachments/VesselInventoryError.png'
if system.file.fileExists(f):
    project.util.openNetworkFile(f)
else:
    system.gui.warningBox('File not found: ' + f)

Adjust the project.util path to wherever the function lives in your project library. If filenames can contain other reserved characters, replace the chained replace() calls with urllib.quote(path, '/:') after import urllib. That call encodes everything except the separators and the drive colon.

Check: the printed URL for the test file matches the known-good literal from the previous section character for character.

Which path details still break the call?

Check: run the function against a test file whose name contains a space, a #, and a % on the same share. It must open without edits to the calling script.

How do I verify the fix end to end?

1. Publish the project and restart or update the Vision client on an operator workstation. Test on the operator workstation, not in the Designer.
2. Log in with the operator Windows account and confirm \\srv-01\share opens in Explorer.
3. Press the button for the original work-order attachment. Read the printed URL in the client console and confirm it starts with file://srv-01/ and contains _NGB%20Work%20Orders.
4. Confirm VesselInventoryError.png opens in the registered image viewer.
5. Repeat with a mapped-drive path and confirm the printed URL starts with file:/// followed by the drive letter.
6. Repeat with a nonexistent filename and confirm the warning box appears and no openURL call is logged.
7. Open the same attachment from a second client PC with a different drive-letter mapping and confirm the UNC path opens identically on both.

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