## Web/Advanced JSON Cutifier (74 solves)> My homework was to write a JSON beautifier. Just Indenting JSON files was too boring that's why I decided to add some features to my project using a popular (More than 1k stars on GitHub!! ) library to make my project more exciting. Important: You can't read any file other than /flag.txt on the remote environment.
Looking at the source code provided first we can see a redacted Go library from github.
```goimport (    "net/http"    "github.com/gin-gonic/gin"    "github.com/REDACTED/REDACTED")```
I cause some errors on the server to try and identify the library:```Expected token OPERATOR but got "}"Expected a comma before next field```
Both these errors point towards the [go-jsonnet](https://github.com/google/go-jsonnet) library, which meets the stars requirement in the challenge description.
I end up looking for ways to read files in the issues section of the repo and find [this issue](https://github.com/google/go-jsonnet/issues/337).
It mentions a payload like the following:
```json{    "wow so advanced!!": importstr "/flag.txt”}```
Running it in the parser we are given the flag:
```json{   "wow so advanced!!": "MAPNA{5uch-4-u53ful-f347ur3-a23f98d}\n\n"}```
Flag: `MAPNA{5uch-4-u53ful-f347ur3-a23f98d}`
**Files:** [player_a466f9f2a43ac42473015d72342c262e8d4b9519.txz](https://web.archive.org/web/20240121175642/https://mapnactf.com/tasks/player_a466f9f2a43ac42473015d72342c262e8d4b9519.txz)