ManifestStartUrlExtractor

Extract the raw start_url string from manifest JSON, reporting whether it is present without applying browser fallback behavior.

Description

A manifest start_url declares a launch destination that may be relative to the manifest URL.

A manifest start_url declares a launch destination that may be relative to the manifest URL. Extracting its raw text cannot resolve it without that base.^[1]

Extract the raw start_url string from manifest JSON, reporting whether it is present without applying browser fallback behavior.

When to use ManifestStartUrlExtractor

Use this tool to extract the raw start_url string from manifest JSON, reporting whether it is present without applying browser fallback behavior.

Choose the URL, decoded source text, header value or explicit byte list requested by this tool. Paste the complete relevant input and follow its parsing and encoding conventions.

How to use ManifestStartUrlExtractor and understand its results

Choose the URL, decoded source text, header value or explicit byte list requested by this tool. Paste the complete relevant input and follow its parsing and encoding conventions.
Enter manifest using the field table and calculation rules, then run the tool.
Read value, found. The explanation below defines the units, signs, ordering and any flags or placeholder values.
If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.

Input field	Meaning	Value type; see rules below	Requirement
manifest	Web application manifest JSON.	string; maximum length: 1000000	Required

Paste manifest JSON text. Require an object and a string if start_url is present. Return the unchanged string and found=true, even when empty. A missing member produces empty value with found=false; malformed JSON and non-string members are errors.

found=typeof manifest.start_url==='string'; value=found ? start_url : ''

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
value	Raw manifest member, empty when absent.	string; maximum length: 1000000
found	Whether a string member was present.	boolean

json

{
  "input": {
    "manifest": "{\"start_url\":\"/app?mode=standalone\"}"
  },
  "output": {
    "value": "/app?mode=standalone",
    "found": true
  }
}

Limitations and assumptions

The tool does not resolve relative URLs, enforce same-origin/scope rules or apply browser launch fallbacks. No manifest or start page is fetched.

Numeric inputs must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Extremely large text inputs are rejected. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.

Alternative or Complementary methods

Use ManifestThemeColorExtractor: Extract the raw theme_color string from manifest JSON, reporting whether it is present without applying browser fallback behavior. For a complementary task, use URL Is Relative: Check whether a reference needs a base URL and resolves against a hierarchical HTTPS base.

References

ManifestStartUrlExtractor — tool.io

Similar or alternative tools

ManifestThemeColorExtractor
Extract the raw theme_color string from manifest JSON, reporting whether it is present without applying browser fallback behavior.
URL Is Relative
Check whether a reference needs a base URL and resolves against a hierarchical HTTPS base.