Marketplace Listing Helper: From a spreadsheet to listings - Part 4

~6 min read

With the importer working, I fed it the real thing: a spreadsheet of Warhammer stock called warhammer-items.csv. It did not import cleanly, and the reasons are a good tour of what "my data" looks like next to what a tool expects.

What the sheet looked like

Nine columns: Item, Brand, Range, Faction, Status, Quantity, Retail, Avg eBay Sold, Market vs Retail (£). It was a stock-take, not a set of listings. Three things stood in the way.

1. No price column. The importer looks for price, asking price, £ or price (£). My sheet had Avg eBay Sold and Retail. Every item would have imported with a blank price.
2. Status meant something else. In the sheet it was Built or BNIB (brand new in box). In the extension, status is draft, listed or sold, and the renew logic reads it. Importing as-is would have put model condition where listing state belongs.
3. Junk rows. Thirteen blank rows, then a totals row (£940.00, £950.00, -£154.00) that would have imported as an item.

Item was the one column that already worked: it's an alias for the title.

A conversion script, not a looser importer

I could have taught the importer to guess. I didn't, for the same reason as in part 3: the extension's fields have fixed meanings, and a guess that is wrong 5% of the time silently corrupts a list. Instead a short one-off script reshapes the sheet into the extension's columns and leaves the importer strict:

| Extension field | Built from | |---|---| | id | generated, 1 to 36, so photo auto-pairing by <id>-*.jpg works | | title | brand + item, quantity if more than 1, then range and faction | | price | Avg eBay Sold with the £ removed, used as-is | | condition | BNIB becomes "New", Built becomes "Used - Good" | | description | generated: brand, range, faction, "Brand new in box" or "Built, not painted", quantity | | category | "Toys & Games" | | status | draft |

The original Status is kept as a Build state column rather than discarded, along with Quantity, Brand, Range, Faction and Retail, because the importer carries unknown columns through. Rows with no item name (the blank rows and the totals row) are skipped, which leaves 36 items.

Titles

Titles were the part I changed my mind about. The first pass gave Warhammer Ushabti x4. But a buyer searching Marketplace for "Tomb Kings" would never find that, and range and faction are exactly what people search for. So the title now reads Warhammer Ushabti x4 - Pre-Sigmar 6th Tomb Kings, and Warhammer Hammerhead - 40k Tau. Where the range and faction are the same word (40k and 40k) it isn't repeated. The longest title is 83 characters, under Facebook's limit of 100, and the script truncates at 100 as a backstop.

Two small rules were forced by the data: quantities like 1 & 6 go into the title as x1 & 6 rather than being parsed, and a quantity of 1 is left out.

Prices

I took the average eBay sold price as the asking price, as-is, as a first pass. A few items sell for more than retail, such as Settra and the Casket of Souls, so those are worth a second look by hand. Three rows had no status in the sheet at all, so they have no condition, and the editor is the place to set them.

A warning I wrote down

Because the importer matches rows by id and lets CSV values win, re-importing a regenerated file overwrites any edits made in the extension to those items. Changing the title format and regenerating is fine if nothing has been edited yet; once it has, it's safer to patch the few fields that changed than to re-import everything.

I checked the round trip in Node: import the file, export it, import that, and the output is byte-for-byte identical. That says the CSV code is stable. It does not say anything about how it behaves in Chrome, which I'll be checking by hand.

What this adds up to

Converting the sheet outside the tool kept the tool simple and honest. The extension's fields keep their meanings, the odd cases (quantities, missing statuses, a totals row) are handled in a script I can read and re-run, and the original columns survive.

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