Michael Chus
40d1c303bb
- go-logging: slog, server-side only, structured attributes - go-database: MySQL cursor safety, soft delete, GORM tags, fail-fast, N+1 prevention - go-background-tasks: Task Manager pattern, polling, no SSE - go-code-style: layering, error wrapping, startup sequence, config, templating - import-export: CSV Excel-compatible rules (BOM, semicolon, decimal comma, DD.MM.YYYY) - table-management: filtering and pagination rules added - CLAUDE.template.md: updated to reference all shared contracts Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
79 lines
2.6 KiB
Markdown
79 lines
2.6 KiB
Markdown
# Contract: Import / Export Workflows
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## Import Workflow
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Recommended stages:
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1. `Upload`
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2. `Preview / Validate`
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3. `Confirm`
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4. `Execute`
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5. `Result summary`
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Rules:
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- Validation preview must be human-readable (table/list), not raw JSON only.
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- Warnings and errors should be shown per row and in aggregate summary.
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- Confirm step should clearly communicate scope and side effects.
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## Export Workflow
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- User must explicitly choose export scope (`selected`, `filtered`, `all`) when ambiguity exists.
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- Export format should be explicit (`csv`, `json`, etc.).
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- Download response must set:
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- `Content-Type: text/csv; charset=utf-8`
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- `Content-Disposition: attachment; filename="..."`
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## CSV Format Rules (Excel-compatible)
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These rules are **mandatory** whenever CSV is exported for spreadsheet users.
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### Encoding and BOM
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- Write UTF-8 BOM (`\xEF\xBB\xBF`) as the very first bytes of the response.
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- Without BOM, Excel on Windows opens UTF-8 CSV as ANSI and garbles Cyrillic/special characters.
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```go
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w.Write([]byte{0xEF, 0xBB, 0xBF})
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```
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### Delimiter
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- Use **semicolon** (`;`) as the field delimiter, not comma.
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- Excel in Russian/European locale uses semicolon as the list separator.
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- Comma-delimited files open as a single column in these locales.
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### Numbers
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- Write decimal numbers with a **comma** as the decimal separator: `1 234,56` — not `1234.56`.
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- Excel in Russian locale does not recognize period as a decimal separator in numeric cells.
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- Format integers and floats explicitly; do not rely on Go's default `%v` or `strconv.FormatFloat`.
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- Use a thin non-breaking space (`\u202F`) or regular space as a thousands separator when the value
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benefits from readability (e.g. prices, quantities > 9999).
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```go
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// correct
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fmt.Sprintf("%.2f", price) // then replace "." -> ","
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strings.ReplaceAll(fmt.Sprintf("%.2f", price), ".", ",")
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// wrong — produces "1234.56", Excel treats it as text in RU locale
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fmt.Sprintf("%.2f", price)
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```
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### Dates
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- Write dates as `DD.MM.YYYY` — the format Excel in Russian locale parses as a date cell automatically.
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- Do not use ISO 8601 (`2006-01-02`) for user-facing CSV; it is not auto-recognized as a date in RU locale.
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### Text quoting
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- Wrap any field that contains the delimiter (`;`), a newline, or a double-quote in double quotes.
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- Escape embedded double-quotes by doubling them: `""`.
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- Use `encoding/csv` with `csv.Writer` and set `csv.Writer.Comma = ';'`; it handles quoting automatically.
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## Error Handling
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- Import errors should map to clear user-facing messages.
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- Export errors after streaming starts must degrade gracefully (human-readable fallback).
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