I'm reluctant to call this a pattern. I don't plan to proofread or edit this and I don't plan to make any corrections. This is just a loose set of instructions to make this bag.
(Editted to add): Here is my project page on Ravelry.
Link to the Pattern on Ravelry.
I used all acrylic yarn because it's easily washable and durable and doesn't stretch as badly as cotton.
I used about 250g of Worsted Weight.
With I Hook, chain 49.
Round 1 : hdc in second chain from hook and all the way across, 6 hdc in last chain and working on the bottom of the chain, hdc across, 5 hdc in first chain, join w. sl st to top of chain 2
Round 2 : ch 2, hdc in same st and in each across, 2 hdc in each next 5 hdc, hdc in each st across to last 4, 2 hdc in each, join w. sl st to top of chain 2 (chain 2 counts as a stitch)
Round 3 : ch 2. hdc in same st and in each across, once you get to the area where you have 2 hdc in each stitch, 2 hdc in each next 8 (or 9) sts, hdc across, to last 7 (or 8) groups of 2 hdc, and work 2 hdc in each, join w. sl st to top of chain 2
Notes: At this point, depending on your gauge, you need to make sure it's flat and not wavy, so you may need to do more or less "2 hdc to 1 stitch" groups.
Round 4 : Here is where we begin working the body of the bag; ch 3 (counts as a stitch), dc BLO in next st and all the way around, join w. sl st to top of chain 3
Round 5 : Ch 3, dc in next st, dc dec over next two stitches, dc to other "end" of the bag, where the curve is and somewhere near the middle do another dc dec over two stitches, dc across and sl st to top of beg chain 3
Round 6 - desired length : Repeat rounds 4 and 5 alternating until you reach your desired length and/or width
I did this until my bag was about 12" high, but if you keep going it could get very narrow, so keep an eye on width and stop the decreases once you're happy. You can also not do any decreases at all if you want it to be straight on the sides
Last round : ch. 1 and sc in each st around, join with sl st to chain 1 and fasten off.
Spacing - measure the width at the place where you want to put the handles, for me it was about 1.5" down from the top of the bag.
16" - so, 4.5" in from the two edges of the bag I joined the yarn by sl st around the dc in the row, sl st around next 3 sts, 4 sts total
Chain 2, turn, hdc in next 3 sts, turn.
Repeat last row until strap measures 22", sl st to the body of the bag on the same side, make sure that the strap isn't twisted. I attached it at about 4.5" from edge
That's it, weave in your ends and you're ready to go...! I might line it with some fabric...we'll see.