用于从api获取json数据的url格式

Question

I am new to using apis and the various methods to get data. I have been following a couple of tutorials including this one on fetch method on or XMLHttpRequest method to get data and can do this just with the apis used in the tutorials. I am hoping to use this api but am having trouble, I think with just the form of the url. I am getting this error:

“Access to fetch at ' http://collections.anmm.gov.au/collections ' from origin ' http://localhost:8888 ' has been blocked by CORS policy: No 'Access-Control-Allow-Origin' “

I have tried using "https" to avoid the CORS error but then get this error:

net::ERR_CONNECTION_REFUSED.

I can return json if I past this url directly into the browser: http://collections.anmm.gov.au/collections/json .

What I would like to know is do I just have a problem with the url I am trying or if perhaps there is an issue with the api itself that is preventing me accessing the data.

Thanks in advance for any pointers.

This is my javascript code:

function createNode(element){
  return document.createElement(element);
}

function addClass(cls, el){
  return el.classList.add("cls");

}

function append(parent, el){
  return parent.appendChild(el);
}

const div = document.getElementById('root');
div.setAttribute('class', 'container');

//const url = 'https://randomuser.me/api/?results=100';
//can return data from this url

const url ='http://collections.anmm.gov.au/collections' // returns data if pasted directly into the browser
//const url = 'http://collections.anmm.gov.au/collections/json' // this is the format suggested in the api documentation I think


fetch(url)
  .then((resp)=> resp.json())
  .then(function(data){

    //create and append the list to the ul
    let authors = data.results; // get results

    return collections.map(function(collection){

      let card = createNode('div'),
        //  img = createNode('img'),
          h1 = createNode('h1');

          card.setAttribute('class', 'card');

      img.src = collection.notes.value;
      h1.innerHTML = `${collection.notes.value} ${collection.notes.value}`;

      append(card, h1);
      append(div, card);

    })
  })

.catch(function(error){
  console.log(error)
});

Answer 1

For those looking for help, I found this answer helpful - No 'Access-Control-Allow-Origin' header is present on the requested resource—when trying to get data from a REST API

I changed by code to the following and successfully returned the json I was expecting:

const proxyurl = "https://cors-anywhere.herokuapp.com/";
const url = "http://collections.anmm.gov.au/collections/json"; // site that doesn’t send Access-Control-*
fetch(proxyurl + url) // https://cors-anywhere.herokuapp.com/https://example.com
.then(response => response.json())
.then(contents => console.log(contents))

.then(function(data){

  let authors = data.results;
console.log(authors);
  return authors.map(function(author){

    let card = createNode('div'),
      //  img = createNode('img'),
        h1 = createNode('h1');

        card.setAttribute('class', 'card');

  //  img.src = author.picture.medium;
    h1.innerHTML = `${author.name.first} ${author.name.last}`; 
    //append(card, img); // append all our elements
    append(card, h1);
    append(div, card);

  })
})


.catch(() => console.log("Can’t access " + url + " response. Blocked by browser?"))