File Attachments and Size Management

Learn how to attach files, images, and manage upload sizes effectively.

📎 File Attachment Options

Single Image

notifyme("Plot ready!", image_path="analysis.png")

Multiple Files

notifyme("Results package!", 
         attachments=["plot1.png", "plot2.png", "data.csv"])

Folder Attachments

# Attach all images from a folder (newest first)
notifyme("All plots from analysis!", 
         attachment_folder="./plots/",
         max_attachments=5)  # Limit to 5 newest files

📏 File Size Management

Default Limits

• Images: Auto-optimized to ≤1 MB, max dimension 1024px
• Non-images: 25 MB default limit
• Server limits: Zulip servers typically allow 25-50 MB

Custom Size Limits

# Allow larger files (50 MB)
notifyme("Large dataset!", 
         attachments=["results.tar.gz"],
         max_file_size=50_000_000)

# Restrict to smaller files (5 MB) for slow connections
notifyme("Quick summary!", 
         attachments=["summary.log"],
         max_file_size=5_000_000)

Size Check Behavior

• Oversized files: Skipped with warning message
• Notification still succeeds: Other files upload normally
• Clear feedback: Shows actual vs. limit sizes

Example output for oversized file:

⚠️ File too large: bigdata.csv (47.3 MB > 25.0 MB limit)

🖼️ Image Optimization

Automatic Processing

Images are automatically optimized for faster uploads:

1. Size check: If ≤1 MB and ≤1024px, no changes needed
2. Dimension resize: Scale down to max 1024px on longest side
3. File size optimization: Reduce quality/compression if still too large
4. Fallback: Use original if optimization fails

Supported Formats

• PNG, JPG/JPEG, GIF, SVG, WebP, BMP, TIFF/TIF

Best Practices for Images

# Good: Generate plots with reasonable size
using Plots
plot(data, size=(800, 600), dpi=150)
savefig("plot.png")
notifyme("Analysis complete!", image_path="plot.png")

# Good: Use PNG for plots, JPEG for photos
savefig("scientific_plot.png")    # Crisp lines and text
savefig("photo_result.jpg")       # Natural images

# Avoid: Extremely high DPI unless necessary
# plot(data, dpi=600)  # Creates very large files

📦 Batch File Handling

Process Multiple Results

# Send all CSV files from results folder
result_files = filter(f -> endswith(f, ".csv"), readdir("results", join=true))
notifyme("All CSV results ready!", 
         attachments=result_files,
         max_attachments=10)

# Send plots with size control
plot_files = filter(f -> endswith(f, r"\.(png|jpg)$"i), readdir("plots", join=true))
notifyme("Plot gallery!", 
         attachments=plot_files,
         max_file_size=10_000_000,  # 10 MB limit per file
         zulip_channel="plots")

Smart File Selection

# Send only recent files (last 24 hours)
recent_files = filter(readdir("output", join=true)) do file
    stat(file).mtime > time() - 24*3600  # 24 hours ago
end

notifyme("Recent outputs!", attachments=recent_files)

# Send largest files first (for data summaries)
data_files = readdir("data", join=true)
sorted_files = sort(data_files, by=filesize, rev=true)
notifyme("Top 3 largest results!", 
         attachments=sorted_files[1:min(3, end)])

🚫 File Upload Errors

Common Issues and Solutions

File not found:

# Check file exists before sending
file_path = "results.png"
if isfile(file_path)
    notifyme("Results!", image_path=file_path)
else
    notifyme("❌ Results file missing: $file_path")
end

Server rejection (413 error):

• File exceeds Zulip server limit
• Try increasing max_file_size if server allows
• Split large files or compress data
• Upload to external storage and share link instead

Image optimization failed:

• Install image processing packages: Pkg.add(["Images", "FileIO", "ImageTransformations"])
• Use original file if optimization not critical
• Convert to supported format (PNG/JPEG)

Fallback Strategies

# Try attachment, fallback to message-only
function safe_notify_with_file(msg, file_path)
    try
        if isfile(file_path) && filesize(file_path) < 25_000_000
            notifyme(msg, image_path=file_path)
        else
            size_mb = round(filesize(file_path) / 1_000_000, digits=1)
            notifyme("$msg\n\n📎 File available locally: $file_path ($(size_mb) MB)")
        end
    catch e
        notifyme("$msg\n\n⚠️ File attachment failed: $e")
    end
end

📋 Summary

Best Practices:

1. Keep images reasonably sized (PNG for plots, moderate DPI)
2. Use max_file_size for network-aware uploads
3. Test file uploads with small files first
4. Monitor server limits and adjust accordingly
5. Implement fallbacks for critical notifications

Default Behavior:

• Images: Auto-optimized to ≤1 MB, ≤1024px
• Non-images: 25 MB limit, skipped if larger
• Multiple files: Processed individually, failures don't stop others
• Folders: Newest files first, respects max_attachments