Write Operations: Create, Update & Delete

Creating Content

Use POST requests to create new content.

Creating a Post

async function createPost(data) {
    const response = await fetch('/wp-json/wp/v2/posts', {
        method: 'POST',
        headers: {
            'Authorization': `Bearer ${token}`,
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({
            title: data.title,
            content: data.content,
            excerpt: data.excerpt,
            status: 'publish',  // or 'draft'
            categories: [5, 6],
            tags: [10, 11],
            featured_media: 123,  // Media ID
            meta: {
                custom_field: 'value'
            }
        })
    });
    
    if (!response.ok) {
        const error = await response.json();
        throw new Error(error.message);
    }
    
    return response.json();  // Returns created post with ID
}

Creating a Page

async function createPage(title, content, parentId = 0) {
    const response = await fetch('/wp-json/wp/v2/pages', {
        method: 'POST',
        headers: {
            'Authorization': `Bearer ${token}`,
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({
            title,
            content,
            status: 'publish',
            parent: parentId,  // For child pages
            menu_order: 0,
            template: ''  // Page template slug
        })
    });
    
    return response.json();
}

Uploading Media

async function uploadMedia(file) {
    const formData = new FormData();
    formData.append('file', file);
    formData.append('title', file.name);
    formData.append('alt_text', 'Image description');
    
    const response = await fetch('/wp-json/wp/v2/media', {
        method: 'POST',
        headers: {
            'Authorization': `Bearer ${token}`
            // Don't set Content-Type - browser sets it with boundary
        },
        body: formData
    });
    
    return response.json();  // Returns media object with ID
}

// Usage with featured image
const media = await uploadMedia(imageFile);
const post = await createPost({
    title: 'My Post',
    content: 'Post content',
    featured_media: media.id
});

Updating Content

Use PUT (full update) or PATCH (partial update).

Updating a Post

async function updatePost(postId, updates) {
    const response = await fetch(`/wp-json/wp/v2/posts/${postId}`, {
        method: 'PUT',  // or 'PATCH' for partial
        headers: {
            'Authorization': `Bearer ${token}`,
            'Content-Type': 'application/json'
        },
        body: JSON.stringify(updates)
    });
    
    return response.json();
}

// Update only specific fields
await updatePost(123, {
    title: 'Updated Title'
});

// Update multiple fields
await updatePost(123, {
    title: 'New Title',
    content: 'Updated content',
    status: 'draft',
    categories: [7, 8]
});

Updating Meta Fields

// Meta fields must be registered with 'show_in_rest' => true
await updatePost(123, {
    meta: {
        _custom_field: 'new value',
        _another_field: 42
    }
});

// In your plugin or theme
register_post_meta('post', '_custom_field', [
    'show_in_rest' => true,
    'single'       => true,
    'type'         => 'string',
    'auth_callback' => function() {
        return current_user_can('edit_posts');
    }
]);

Deleting Content

Use DELETE requests. By default, posts go to trash.

Delete (Trash) a Post

async function trashPost(postId) {
    const response = await fetch(`/wp-json/wp/v2/posts/${postId}`, {
        method: 'DELETE',
        headers: {
            'Authorization': `Bearer ${token}`
        }
    });
    
    return response.json();  // Returns trashed post
}

Permanently Delete

async function deletePost(postId, force = false) {
    const url = force 
        ? `/wp-json/wp/v2/posts/${postId}?force=true`
        : `/wp-json/wp/v2/posts/${postId}`;
    
    const response = await fetch(url, {
        method: 'DELETE',
        headers: {
            'Authorization': `Bearer ${token}`
        }
    });
    
    return response.json();
}

// Trash (can be restored)
await deletePost(123);

// Permanently delete
await deletePost(123, true);

Working with Terms

Create a Category

async function createCategory(name, parent = 0) {
    const response = await fetch('/wp-json/wp/v2/categories', {
        method: 'POST',
        headers: {
            'Authorization': `Bearer ${token}`,
            'Content-Type': 'application/json'
        },
        body: JSON.stringify({
            name,
            parent,
            description: '',
            slug: ''  // Auto-generated if empty
        })
    });
    
    return response.json();
}

Assign Terms to Post

// Categories and tags are arrays of term IDs
await updatePost(123, {
    categories: [1, 2, 3],
    tags: [10, 11, 12]
});

Bulk Operations

The API doesn't have built-in bulk operations, but you can use Promise.all:

async function bulkUpdateStatus(postIds, status) {
    const updates = postIds.map(id => 
        updatePost(id, { status })
    );
    
    return Promise.all(updates);
}

// Update multiple posts to draft
await bulkUpdateStatus([1, 2, 3, 4, 5], 'draft');

Error Handling

async function safeApiCall(endpoint, options) {
    try {
        const response = await fetch(endpoint, options);
        const data = await response.json();
        
        if (!response.ok) {
            // WordPress returns error details
            return {
                success: false,
                code: data.code,
                message: data.message,
                data: data.data
            };
        }
        
        return { success: true, data };
        
    } catch (error) {
        return {
            success: false,
            code: 'network_error',
            message: error.message
        };
    }
}

// Usage
const result = await safeApiCall('/wp-json/wp/v2/posts', {
    method: 'POST',
    headers: { /* ... */ },
    body: JSON.stringify({ title: '' })  // Empty title = error
});

if (!result.success) {
    console.error(`${result.code}: ${result.message}`);
    // "rest_invalid_param: title is required"
}

Next Steps

In the next lesson, we'll build custom REST endpoints for your own data and functionality.