byIsbn method sometimes return null

[mdeprezzo]

HI,
i notice that sometime, the byIsbn method from Voumes class, return null. But from google books api console, i see the results. So i need to delete the string 'isbn' and now work fine. Any suggestions ?

[josephmancuso]

I believe when you loop through this, you'll need to check if it is not null before displaying it since you obviously can't echo null

[mdeprezzo]

The point is, if i remove 'isbn:' works fine, i can find the books. But if i restore that string, null is the result.

[josephmancuso]

Can you post your code?

[mdeprezzo]

Sure, i simply make a call to findByGoogleBooks:

	/**
	 * @param GoogleBooks $googlebooks
	 */
	public function __construct(GoogleBooks $googlebooks)
	{
		$this->googlebooks = $googlebooks;
	}

	/**
	 * Attempt to find a book by isbn from google books
	 * 
	 * @param String $isbn
	 * @return Response
	 */
	public function findByGoogleBooks($isbn)
	{
		return $this->googlebooks->volumes->byIsbn($isbn);
	}	

Maybe i need to call search instead of byisbn

[josephmancuso]

that method only takes the ISBN. https://github.com/scriptotek/php-google-books/blob/master/src/Volumes.php#L41

I believe what you are saying is you are doing something like:

...->findByGoogleBooks('isbn: 8ynsf...')

it should just be the isbn

...->findByGoogleBooks('8ynsf...')

since we prepend that isbn string. check the link to the Volumes class

[mdeprezzo]

@josephmancuso i know, but with prefix 'isbn:' i have always null or empty data, returned from api. But in reality the books exists if i test the call with postman.

[josephmancuso]

ahhh ok I see. So removing the 'isbn:' from the volumes class fixes the issue you're saying?

@danmichaelo

[mdeprezzo]

@josephmancuso yep, maybe something is changed on google books api. But I could not understand why it did not work anymore, and to test it, i've tried to remove 'isbn:'.

[josephmancuso]

hm it looks like the 'isbn:' still works via the google books api.

GET https://www.googleapis.com/books/v1/volumes?q=isbn%3A9780735619678&key={YOUR_API_KEY}

I'll test the actual code some time today. There are two PRs open that significantly change the API for this repo but a hot fix can work for the master branch. @danmichaelo is the owner

if you want to open a PR for the master branch go ahead. I'll test today.

[mdeprezzo]

With italian isbn doesn't works yet, like 9788807902246

[josephmancuso]

Well ISBN are international. That's what the I stands for. They're either 13 digits or 10 digits. I'll test both

[mdeprezzo]

Of course, then maybe it's google books that has not added all the titles in the world in its archive? :D

[danmichaelo]

Hm, this is quite interesting. If you look at the response for 9788807902246, it seems to refer to another book. Here's an excerpt:

    {
        "title": "Paddy Clarke ha ha ha",
        "authors": [
          "Roddy Doyle"
        ],
        "publishedDate": "1996",
        "industryIdentifiers": [
          {
            "type": "ISBN_10",
            "identifier": "8202160278"
          },
          {
            "type": "ISBN_13",
            "identifier": "9788202160272"
          }
        ],

At first I though it was the same book with another ISBN, but when I googled the same ISBN, I found the book Sull'Apocalisse. Testo latino a fronte by di Gioacchino da Fiore (2018) – a very different book.

So it seems like the Google Books API can return information about the wrong item if you just do a free query without the isbn: prefix. Do you have any other ISBN numbers we can test with?

[josephmancuso]

@danmichaelo what was the exact query you put in? I actually noticed a discrepancy if there was a space between isbn: and the number. No space returned 1 result and a space returned like 1600 results

[mdeprezzo]

@danmichaelo Sure, give me a few minutes to make a list of problematic isbn.

here we go:

9788845426544
9788811689188

[danmichaelo]

@danmichaelo what was the exact query you put in? I actually noticed a discrepancy if there was a space between isbn: and the number. No space returned 1 result and a space returned like 1600 results

The query can be found in the link I added ;) No key is needed. But the strange part is that I get a different (and seemingly correct) result now! Could it just have been a temporary problem at Google?

For 9788845426544 and 9788811689188 I get zero results both with and without the isbn: prefix, so that is not the same issue.